Resolve "Fix broken Service Ping metric queries"

What does this MR do and why?

Describe in detail what your merge request does and why.

Resolves #353559 (closed)

summary: During work around !81002 (merged) it was identified that some of generated by https://gitlab.com/gitlab-org/gitlab/-/blob/master/lib/gitlab/usage/service_ping_report.rb#L39 SQL queries used at https://docs.gitlab.com/ee/api/usage_data.html#export-service-ping-sql-queries have invalid SQL syntax

The syntax errors were due to the following issues

1. Invalid syntax due to order_by
   • counts.labels is the only one in this category
   • Labels model has a default_scope order(title: :asc) which interferes with the count sql statement
   • Resolution: Adding unscope(:order) to handle this
2. Incorrect value datatype (nil vs 0)
   • When service ping report is generated for all_metrics_values, it calls .send(:count) which type casts values to int
   • eg. counts.jira_imports_total_imported_issues_count returns nil when executed as query, but expects 0
   • Resolution: Type casting the values to handle this
3. Joins with select column on joined table
   • In case of joins, when the selected column is of the format table2.column, the generated query is of format select count(table1.table2.column) from ... which is invalid syntax
   • eg. usage_activity_by_stage.create.projects_with_sectional_code_owner_rules
   • Resolution: Checking for joins before building the query

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How to set up and validate locally

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

1. run the test with bin/rspec spec/lib/gitlab/usage/service_ping_report_spec.rb:94 to verify

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