[FLINK-21400][ci] Enables FileSink and Stateful stream job e2e test for the AdaptiveScheduler

[XComp]

What is the purpose of the change

Increases test coverage for AdaptiveScheduler. FLINK-21400 was fixed. No need to have these tests disabled.

Brief change log

• Removes if condition

Verifying this change

This change is a trivial rework / code cleanup without any test coverage.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): no
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable

[flinkbot]

CI report:

• bb87776 Azure: PENDING

Bot commands

The @flinkbot bot supports the following commands:

• @flinkbot run azure re-run the last Azure build

[XComp]

Closing the issue in favor of FLINK-34409