[DataAvailability] Add functional tests for processing pipeline

[Guitarheroua]

Closes: https://github.com/onflow/flow-go/issues/7379

NOTE: Check only pipeline_functional_test.go

DEPENDS ON: https://github.com/onflow/flow-go/pull/7514, https://github.com/onflow/flow-go/pull/7523

Introduces functional test for pipeline workflow, to check it with real database, storages and components.

[codecov-commenter]

Codecov Report

:x: Patch coverage is 93.39623% with 7 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...iondatasync/optimistic_sync/pipeline_test_utils.go	88.13%	5 Missing and 2 partials :warning:

:loudspeaker: Thoughts on this report? Let us know!

[Guitarheroua]

thanks for refactoring. added a few comments for additional test cases.

Please, do not review it yet, as I am finishing with additional test cases.