Implement `Logger#enabled?`

Spec requirement

Logger SHOULD provide an Enabled function (api.md:105-107,131-157 (L105-L107, L131-L157)); the No-Op Enabled MUST always return false (noop.md:60-62 (permalink)); the SDK's Enabled MUST return false when there are no registered LogRecordProcessors or when all registered processors implement Enabled and return false, otherwise SHOULD return true (sdk.md:263-278 (permalink)); a LogRecordProcessor MAY implement its own Enabled to support this filtering (sdk.md:429-464 (permalink)).

Current behavior

No enabled?/enabled method exists on OpenTelemetry::Logs::Logger (logs_api/lib/opentelemetry/logs/logger.rb (permalink)), the SDK Logger (logs_sdk/lib/opentelemetry/sdk/logs/logger.rb (permalink)), the base LogRecordProcessor (logs_sdk/lib/opentelemetry/sdk/logs/log_record_processor.rb (permalink)), or either built-in processor.

Suggested fix

Add enabled to the no-op Logger (always false); add it to the SDK Logger (false if no processors are registered, else true unless every processor implements and returns false from its own Enabled); add an optional Enabled hook to LogRecordProcessor/SimpleLogRecordProcessor/BatchLogRecordProcessor.

Related rows in SPEC_COMPLIANCE_LOGS.md

API-8, API-11, NOOP-4, SDK-23, SDK-35

Review the API Logger, SDK Logger, LogRecordProcessor, SimpleLogRecordProcessor, and BatchLogRecordProcessor files named in the issue, starting with their current interfaces and processor registration flow. Implement the specified no-op, SDK, and processor-hook behavior, then verify it against the linked OpenTelemetry logs API, no-op, and SDK requirements and the API-8, API-11, NOOP-4, SDK-23, and SDK-35 compliance rows.