Backfill all ProjectSetting records

What does this MR do and why?

Backfills missing project_settings record. This is a follow-up to fixing the automatic creation of project_settings record for each project in !84502 (merged).

Related to https://gitlab.com/gitlab-org/gitlab/-/issues/356268.

Screenshots or screen recordings

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Migration output

up

$ rake db:migrate:up VERSION=20220324165436                                                                                                                                                                     
== 20220324165436 ScheduleBackfillProjectSettings: migrating ==================
== 20220324165436 ScheduleBackfillProjectSettings: migrated (0.0372s) =========

down

$ rake db:migrate:down VERSION=20220324165436                                                                                                                                                                   
== 20220324165436 ScheduleBackfillProjectSettings: reverting ==================
== 20220324165436 ScheduleBackfillProjectSettings: reverted (0.0148s) =========

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

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