[FLINK-37308] Support pauseOrResumeSplits in HybridSource

[xccui]

What is the purpose of the change

This PR added the pauseOrResumeSplits implementation in HybridSourceReader.

Brief change log

Delegate it to the current reader.

Verifying this change

A new testPauseResumeCurrentSourceSplits test was added to HybridSourceReaderTest.java.

Also verified the change with a production job.

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:

• 3a64f25 Azure: SUCCESS

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[Copilot]

Pull Request Overview

This PR adds support for pausing or resuming splits in the HybridSourceReader by delegating the request to the current underlying reader. It also introduces a new test to validate the behavior.

• Implement pauseOrResumeSplits in HybridSourceReader.
• Add testPauseResumeCurrentSourceSplits in HybridSourceReaderTest.
• Update import statements to support the new method signature.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
HybridSourceReaderTest.java	Added a test that verifies pause and resume propagation to the underlying reader.
HybridSourceReader.java	Delegated the pauseOrResumeSplits call to the current reader.