Fix ClassCastException for CassandraObservationContext

[cfredri4]

This fixes a ClassCastException for CassandraObservationContext when a NoopObservation is returned by the observation registry.

2024-11-28 10:46:44.837+0100 [s1-admin-0] WARN  c.d.o.d.i.core.tracker.MultiplexingRequestTracker - [warnWithException] [s1|2034963355] Unexpected error while notifying request tracker INSTANCE of an onNodeSuccess event.
java.lang.ClassCastException: class io.micrometer.observation.Observation$Context cannot be cast to class org.springframework.data.cassandra.observability.CassandraObservationContext (io.micrometer.observation.Observation$Context and org.springframework.data.cassandra.observability.CassandraObservationContext are in unnamed module of loader 'app')
	at org.springframework.data.cassandra.observability.ObservationRequestTracker.onNodeSuccess(ObservationRequestTracker.java:109)
	at com.datastax.oss.driver.internal.core.tracker.MultiplexingRequestTracker.lambda$onNodeSuccess$2(MultiplexingRequestTracker.java:114)
	at com.datastax.oss.driver.internal.core.tracker.MultiplexingRequestTracker.invokeTrackers(MultiplexingRequestTracker.java:155)
	at com.datastax.oss.driver.internal.core.tracker.MultiplexingRequestTracker.onNodeSuccess(MultiplexingRequestTracker.java:113)
	at com.datastax.oss.driver.internal.core.cql.CqlRequestHandler.setFinalResult(CqlRequestHandler.java:338)
	at com.datastax.oss.driver.internal.core.cql.CqlRequestHandler.access$1500(CqlRequestHandler.java:97)
	at com.datastax.oss.driver.internal.core.cql.CqlRequestHandler$NodeResponseCallback.lambda$onResponse$1(CqlRequestHandler.java:648)
...
2024-11-28 10:46:44.840+0100 [s1-admin-0] DEBUG o.s.d.c.observability.ObservationRequestTracker - [onSuccess] Closing observation [io.micrometer.observation.NoopObservation@56c0e4a0]

2024-11-28 10:46:44.893+0100 [s1-io-3] WARN  c.d.o.d.i.core.tracker.MultiplexingRequestTracker - [warnWithException] [s1|1865288005] Unexpected error while notifying request tracker INSTANCE of an onNodeSuccess event.
java.lang.ClassCastException: class io.micrometer.observation.Observation$Context cannot be cast to class org.springframework.data.cassandra.observability.CassandraObservationContext (io.micrometer.observation.Observation$Context and org.springframework.data.cassandra.observability.CassandraObservationContext are in unnamed module of loader 'app')
	at org.springframework.data.cassandra.observability.ObservationRequestTracker.onNodeSuccess(ObservationRequestTracker.java:109)
	at com.datastax.oss.driver.internal.core.tracker.MultiplexingRequestTracker.lambda$onNodeSuccess$2(MultiplexingRequestTracker.java:114)
	at com.datastax.oss.driver.internal.core.tracker.MultiplexingRequestTracker.invokeTrackers(MultiplexingRequestTracker.java:155)
	at com.datastax.oss.driver.internal.core.tracker.MultiplexingRequestTracker.onNodeSuccess(MultiplexingRequestTracker.java:113)
	at com.datastax.oss.driver.internal.core.cql.CqlRequestHandler.setFinalResult(CqlRequestHandler.java:338)
	at com.datastax.oss.driver.internal.core.cql.CqlRequestHandler.access$1500(CqlRequestHandler.java:97)
	at com.datastax.oss.driver.internal.core.cql.CqlRequestHandler$NodeResponseCallback.onResponse(CqlRequestHandler.java:657)
...
2024-11-28 10:46:44.905+0100 [s1-io-3] DEBUG o.s.d.c.observability.ObservationRequestTracker - [onSuccess] Closing observation [io.micrometer.observation.NoopObservation@56c0e4a0]

[mp911de]

Paging @marcingrzejszczak

[mp911de]

Thank you for your contribution. That's merged, polished, and backported now.