Resolve "Service ping integration with batched background migrations"

What does this MR do and why?

We are introducing a new metric to the service ping in this merge request.

The goal of this metric is to collect the number of failed jobs per batched background migration. This information will help us to understand the impact of batched background migrations in self-host customers.

Query:

SELECT "batched_background_migrations"."table_name", "batched_background_migrations"."job_class_name", COUNT(batched_jobs) AS number_of_failed_jobs FROM "batched_background_migrations" INNER JOIN "batched_background_migration_jobs" "batched_jobs" ON "batched_jobs"."batched_background_migration_id" = "batched_background_migrations"."id" WHERE "batched_jobs"."status" = 2 GROUP BY "batched_background_migrations"."table_name", "batched_background_migrations"."job_class_name" ORDER BY table_name, job_class_name

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How to set up and validate locally

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MR acceptance checklist

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Related to #416718 (closed)