[FLINK-40303][table] Skip non-key NOT NULL checks for key-only deletes

[Au-Miner]

What is the purpose of the change

Key-only DELETE records set non-key fields to null. When a sink declares NOT NULL constraints on non-key columns, the constraint enforcer incorrectly rejects these valid DELETE records.

Brief change log

• Pass the input changelog's key-only DELETE semantic and sink primary key indices from CommonExecSink to ConstraintEnforcerExecutor.
• Update NotNullConstraint to skip non-key fields for key-only DELETE records while continuing to validate primary key fields.
• Add semantic coverage for writing a key-only DELETE to a sink with a NOT NULL non-key column.

Verifying this change

Added INSERT_SELECT_DELETE_BY_KEY_DELETE_BY_KEY_WITH_NOT_NULL_SINK to DeletesByKeySemanticTests. The test covers a key-only source and sink, verifies that ChangelogNormalize can remain eliminated, and expects -D[1, null] to be accepted by a sink whose non-key column is NOT NULL.

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:

• ee4dfb9 Azure: SUCCESS

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