[BP-2.0][FLINK-37276] Add missing state v2 access interfaces in RuntimeContext

[Zakelly]

Backport to 2.0 for #26120

What is the purpose of the change

We have introduced the state v2 creating methods in StreamingRuntimeContext, but these methods have not exposed to RuntimeContext. Thus user may not be able to access the state via getRuntimeContext().getState.

Brief change log

• Add Add constructors for state v2 descriptors that accept type class
• Add state access interfaces in RuntimeContext

Verifying this change

This change is a trivial work 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:

• 6cd3eca Azure: SUCCESS

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