[FLINK-36484] [TABLE-SQL] Remove deprecated methods StreamTableEnvironment#registerFunction

[ammu20-dev]

What is the purpose of the change

This Pull request removes the deprecated method mentioned in the issue: https://issues.apache.org/jira/browse/FLINK-36484

Brief change log

Remove deprecated methods.

Verifying this change

This change is already covered by existing tests

(Please pick either of the following options)

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

(or)

This change is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

(example:)

• Added integration tests for end-to-end deployment with large payloads (100MB)
• Extended integration test for recovery after master (JobManager) failure
• Added test that validates that TaskInfo is transferred only once across recoveries
• Manually verified the change by running a 4 node cluster with 2 JobManagers and 4 TaskManagers, a stateful streaming program, and killing one JobManager and two TaskManagers during the execution, verifying that recovery happens correctly.

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

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no)
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): (yes / no / don't know)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (yes / no / don't know)
• The S3 file system connector: (yes / no / don't know)

Documentation

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

[flinkbot]

CI report:

• 02f70f631ea19179e8ebcaddcd766af9f78c0dae Azure: SUCCESS

Bot commands

The @flinkbot bot supports the following commands:

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

[davidradl]

@ammu20-dev please could you amend the title to follow the usual pattern to include the issue number in square brackets and make the title more specific to what you are removing.

[rmetzger]

@twalthr @wuchong is it okay to remove this method?

[ammu20-dev]

@flinkbot run azure

[ammu20-dev]

@xuyangzhong Thanks for the review. Removed the methods from Scala class.