Remove advisor low-cardinality keys that aren't actually exposed.

[habuma]

I noticed that gen_ai.operation.name and gen_ai.system are shown as low-cardinality keys for spring.ai.advisor, but neither of those appear in the metrics. Moreover, I confirmed that are aren't included as low-cardinality keys in either DefaultAdvisorObservationConvention or AdvisorObservationDocumentation. So this PR removes them from the documentation.

[markpollack]

@jonatan-ivanov can you review this please?

[jonatan-ivanov]

gen_ai.operation.name is there as an enum:

spring-ai/spring-ai-core/src/main/java/org/springframework/ai/observation/conventions/AiObservationAttributes.java

Line 38 in efc3923

AI_OPERATION_TYPE("gen_ai.operation.name"),

But it is called AI_OPERATION_TYPE. Type vs. name puzzles me a bit (it seems it is called type everywhere except that value in the enum). It also seems to be used in certain cases, there are even integration tests for it. I would follow through the usage since it seems DefaultChatClientObservationConvention uses it (with other conventions) and if the keyvalue is added metrics should also have this tag:

spring-ai/spring-ai-core/src/main/java/org/springframework/ai/chat/client/observation/DefaultChatClientObservationConvention.java

Lines 63 to 71 in efc3923

	@Override
	public KeyValues getLowCardinalityKeyValues(ChatClientObservationContext context) {
	return KeyValues.of(aiOperationType(context), aiProvider(context), springAiKind(), stream(context));
	}
	protected KeyValue aiOperationType(ChatClientObservationContext context) {
	return KeyValue.of(ChatModelObservationDocumentation.LowCardinalityKeyNames.AI_OPERATION_TYPE,
	context.getOperationMetadata().operationType());
	}

It seems spring.ai.advisor is not a tag on the metric but the name of it:

spring-ai/spring-ai-core/src/main/java/org/springframework/ai/chat/client/advisor/observation/DefaultAdvisorObservationConvention.java

Lines 34 to 40 in efc3923

	public static final String DEFAULT_NAME = "spring.ai.advisor";
	private final String name;
	public DefaultAdvisorObservationConvention() {
	this(DEFAULT_NAME);
	}

Though metrics are only created when you trigger the operation that records the observation, can it happen that your use-case did not trigger it?