[fix][fn] Return descriptive errors for unknown JSON properties

[zgzyq]

Fixes #18253

Motivation

The Functions Worker APIs return a generic HTTP 400 response when a multipart JSON configuration contains an unknown property. Pulsar already has an UnrecognizedPropertyExceptionMapper that produces a descriptive error, but the Functions Worker resource configurations do not register it.

Modifications

• Register UnrecognizedPropertyExceptionMapper for the Functions Worker V2 APIs.
• Register UnrecognizedPropertyExceptionMapper for the Functions Worker V3 APIs.
• Add a regression test covering both resource sets.

Verifying this change

This change added tests and can be verified as follows:

• ./gradlew :pulsar-functions:pulsar-functions-worker:test --tests "org.apache.pulsar.functions.worker.rest.ResourcesTest" -PtestRetryCount=0
• ./gradlew :pulsar-functions:pulsar-functions-worker:checkstyleMain :pulsar-functions:pulsar-functions-worker:checkstyleTest

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

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment