Avoid adding more than one foreign key within `with_lock_retries`

What does this MR do?

This MR improves the 👮 Migration/WithLockRetriesDisallowedMethod to prevent the usages of more than one add_foreign_key within with_lock_retries and links to https://docs.gitlab.com/ee/development/migration_style_guide.html#examples.

Refs #260317 (comment 422644313)

Example

This is from the current CI 😅 (already fixed within this MR)

Offenses:

db/migrate/20200123090839_remove_analytics_repository_table_fks_on_projects.rb:20:7: C: Migration/WithLockRetriesDisallowedMethod: Avoid adding more than one foreign key with the with_lock_retries. See https://docs.gitlab.com/ee/development/migration_style_guide.html#examples
      add_foreign_key :analytics_repository_files, :projects, on_delete: :cascade
      ^^^^^^^^^^^^^^^
db/migrate/20200123090839_remove_analytics_repository_table_fks_on_projects.rb:21:7: C: Migration/WithLockRetriesDisallowedMethod: Avoid adding more than one foreign key with the with_lock_retries. See https://docs.gitlab.com/ee/development/migration_style_guide.html#examples
      add_foreign_key :analytics_repository_file_edits, :projects, on_delete: :cascade
      ^^^^^^^^^^^^^^^
db/migrate/20200123090839_remove_analytics_repository_table_fks_on_projects.rb:22:7: C: Migration/WithLockRetriesDisallowedMethod: Avoid adding more than one foreign key with the with_lock_retries. See https://docs.gitlab.com/ee/development/migration_style_guide.html#examples
      add_foreign_key :analytics_repository_file_commits, :projects, on_delete: :cascade
      ^^^^^^^^^^^^^^^
db/migrate/20200123091422_remove_analytics_repository_files_fk_on_other_analytics_tables.rb:19:7: C: Migration/WithLockRetriesDisallowedMethod: Avoid adding more than one foreign key with the with_lock_retries. See https://docs.gitlab.com/ee/development/migration_style_guide.html#examples
      add_foreign_key :analytics_repository_file_edits, :analytics_repository_files, on_delete: :cascade
      ^^^^^^^^^^^^^^^
db/migrate/20200123091422_remove_analytics_repository_files_fk_on_other_analytics_tables.rb:20:7: C: Migration/WithLockRetriesDisallowedMethod: Avoid adding more than one foreign key with the with_lock_retries. See https://docs.gitlab.com/ee/development/migration_style_guide.html#examples
      add_foreign_key :analytics_repository_file_commits, :analytics_repository_files, on_delete: :cascade
      ^^^^^^^^^^^^^^^

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• [-] Separation of EE specific content

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• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

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• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
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