Cleanup 'CI runner tokens duplicates cleanup' migrations

What does this MR do and why?

Describe in detail what your merge request does and why.

Following the process for cleaning up migrations, we need to cleanup the migrations introduced by !98689 (merged) in %15.5, and the ones introduced by !83733 (merged) in %15.0.

The migrations have already been finalized before:

$ rg "finalize_background_migration 'ResetDuplicateCiRunnersToken.*Values.*'" db
db/migrate/20220617123144_drop_temp_index_on_projects_on_id_and_runners_token_encrypted.rb
9:    finalize_background_migration 'ResetDuplicateCiRunnersTokenEncryptedValuesOnProjects'

db/post_migrate/20221021082255_add_unique_index_on_ci_runners_token.rb
9:    finalize_background_migration 'ResetDuplicateCiRunnersTokenValues'

db/migrate/20220617123135_drop_temp_index_on_projects_on_id_and_runners_token.rb
9:    finalize_background_migration 'ResetDuplicateCiRunnersTokenValuesOnProjects'

db/post_migrate/20221021082312_add_unique_index_on_ci_runners_token_encrypted.rb
9:    finalize_background_migration 'ResetDuplicateCiRunnersTokenEncryptedValues'

Closes #376709 (closed)

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