[hotfix] Revert the breaking change to the public implementations of RichFunction

[WencongLiu]

What is the purpose of the change

Revert the breaking change to the public implementations of RichFunction. The breaking change was initially introduced by FLINK-32978.

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): (yes)
• 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:

• e04e5ae Azure: SUCCESS

Bot commands

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

[xintongsong]

@WencongLiu, thanks for the PR. LGTM.

Minor: This commit should not be labeled. I'll fix this during merging.