Fix amount_used column precision on ci_project_monthly_usages table

What does this MR do and why?

Parent issue: https://gitlab.com/gitlab-org/gitlab/-/issues/382386
This MR is one of 2 to address the above issue. Other MR can be found here.

Adding following migrations:
20221221171239 Rename amount used column
20221222092958 Sync new amount used with amount used
20230104103748 Remove new amount used column\

Migrations logs:

Migration: 20221221171239 Rename amount used column
on CI database:
UP

✗ rake db:migrate:up:ci VERSION=20221221171239
ci: == 20221221171239 RenameAmountUsedColumn: migrating ===========================
ci: -- rename_column(:ci_project_monthly_usages, :amount_used, :tmp_amount_used)
ci:    -> 0.0728s
ci: -- rename_column(:ci_project_monthly_usages, :new_amount_used, :amount_used)
ci:    -> 0.0021s
ci: -- rename_column(:ci_project_monthly_usages, :tmp_amount_used, :new_amount_used)
ci:    -> 0.0018s
ci: == 20221221171239 RenameAmountUsedColumn: migrated (0.0883s) ==================

DOWN

 ✗ rake db:migrate:down:ci VERSION=20221221171239
ci: == 20221221171239 RenameAmountUsedColumn: reverting ===========================
ci: -- rename_column(:ci_project_monthly_usages, :amount_used, :tmp_amount_used)
ci:    -> 0.0717s
ci: -- rename_column(:ci_project_monthly_usages, :new_amount_used, :amount_used)
ci:    -> 0.0021s
ci: -- rename_column(:ci_project_monthly_usages, :tmp_amount_used, :new_amount_used)
ci:    -> 0.0018s
ci: == 20221221171239 RenameAmountUsedColumn: reverted (0.0897s) ==================

on MAIN database:
UP

✗ rake db:migrate:up:main VERSION=20221221171239
main: == 20221221171239 RenameAmountUsedColumn: migrating ===========================
main: -- rename_column(:ci_project_monthly_usages, :amount_used, :tmp_amount_used)
main:    -> 0.0947s
main: -- rename_column(:ci_project_monthly_usages, :new_amount_used, :amount_used)
main:    -> 0.0023s
main: -- rename_column(:ci_project_monthly_usages, :tmp_amount_used, :new_amount_used)
main:    -> 0.0024s
main: == 20221221171239 RenameAmountUsedColumn: migrated (0.1072s) ==================

DOWN

 ✗ rake db:migrate:down:main VERSION=20221221171239
main: == 20221221171239 RenameAmountUsedColumn: reverting ===========================
main: -- rename_column(:ci_project_monthly_usages, :amount_used, :tmp_amount_used)
main:    -> 0.0895s
main: -- rename_column(:ci_project_monthly_usages, :new_amount_used, :amount_used)
main:    -> 0.0023s
main: -- rename_column(:ci_project_monthly_usages, :tmp_amount_used, :new_amount_used)
main:    -> 0.0018s
main: == 20221221171239 RenameAmountUsedColumn: reverted (0.0992s) ==================

Post-deployment migration: 20221222092958 Sync new amount used with amount used
on CI database:
UP

✗ rake db:migrate:up:ci VERSION=20221222092958
ci: == 20221222092958 SyncNewAmountUsedWithAmountUsed: migrating ==================
ci: == 20221222092958 SyncNewAmountUsedWithAmountUsed: migrated (0.0113s) =========

DOWN

 ✗ rake db:migrate:down:ci VERSION=20221222092958
ci: == 20221222092958 SyncNewAmountUsedWithAmountUsed: reverting ==================
ci: == 20221222092958 SyncNewAmountUsedWithAmountUsed: reverted (0.0247s) =========

on MAIN database:
UP

✗ rake db:migrate:up:main VERSION=20221222092958
main: == 20221222092958 SyncNewAmountUsedWithAmountUsed: migrating ==================
main: -- The migration is skipped since it modifies the schemas: [:gitlab_ci].
main: -- This database can only apply migrations in one of the following schemas: [:gitlab_main, :gitlab_shared, :gitlab_internal, :gitlab_pm].
main: == 20221222092958 SyncNewAmountUsedWithAmountUsed: migrated (0.0009s) =========

DOWN

✗ rake db:migrate:down:main VERSION=20221222092958
main: == 20221222092958 SyncNewAmountUsedWithAmountUsed: reverting ==================
main: -- The migration is skipped since it modifies the schemas: [:gitlab_ci].
main: -- This database can only apply migrations in one of the following schemas: [:gitlab_main, :gitlab_shared, :gitlab_internal, :gitlab_pm].
main: == 20221222092958 SyncNewAmountUsedWithAmountUsed: reverted (0.0009s) =========

Post-deployment migration: 20230104103748 Remove new amount used column
on CI database:
UP

 ✗ rake db:migrate:up:ci VERSION=20230104103748  
ci: == 20230104103748 RemoveNewAmountUsedColumn: migrating ========================
ci: -- remove_column(:ci_project_monthly_usages, :new_amount_used)
ci:    -> 0.0012s
ci: == 20230104103748 RemoveNewAmountUsedColumn: migrated (0.0152s) ===============

DOWN

✗ rake db:migrate:down:ci VERSION=20230104103748
ci: == 20230104103748 RemoveNewAmountUsedColumn: reverting ========================
ci: -- column_exists?(:ci_project_monthly_usages, :new_amount_used)
ci:    -> 0.0790s
ci: -- add_column(:ci_project_monthly_usages, :new_amount_used, :decimal, {:default=>0.0, :precision=>18, :scale=>2, :null=>false})
ci:    -> 0.0014s
ci: == 20230104103748 RemoveNewAmountUsedColumn: reverted (0.1129s) ===============

on MAIN database:
UP

 ✗ rake db:migrate:up:main VERSION=20230104103748
main: == 20230104103748 RemoveNewAmountUsedColumn: migrating ========================
main: -- remove_column(:ci_project_monthly_usages, :new_amount_used)
main:    -> 0.0015s
main: == 20230104103748 RemoveNewAmountUsedColumn: migrated (0.0046s) ===============

DOWN

 ✗ rake db:migrate:down:main VERSION=20230104103748
main: == 20230104103748 RemoveNewAmountUsedColumn: reverting ========================
main: -- column_exists?(:ci_project_monthly_usages, :new_amount_used)
main:    -> 0.1108s
main: -- add_column(:ci_project_monthly_usages, :new_amount_used, :decimal, {:default=>0.0, :precision=>18, :scale=>2, :null=>false})
main:    -> 0.0021s
main: == 20230104103748 RemoveNewAmountUsedColumn: reverted (0.1183s) ===============

How to set up and validate locally

Checkout the branch and run the migration on ci and main db.

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.