Refine tracing exemplar inclusion configuration

[answndud]

Summary

• rename management.tracing.exemplars.filter to management.tracing.exemplars.include and align the values with all, none, and sampled-traces
• stop registering OTLP and Prometheus exemplar support beans when exemplar inclusion is none
• update the tracing docs and regression tests for the revised property and behavior

Testing

• ./gradlew :module:spring-boot-micrometer-tracing:test --tests org.springframework.boot.micrometer.tracing.autoconfigure.otlp.LazyTracingExemplarContextProviderTests --tests org.springframework.boot.micrometer.tracing.autoconfigure.prometheus.LazyTracingSpanContextTests :module:spring-boot-micrometer-tracing-brave:test --tests org.springframework.boot.micrometer.tracing.brave.autoconfigure.OtlpExemplarsAutoConfigurationTests --tests org.springframework.boot.micrometer.tracing.brave.autoconfigure.PrometheusExemplarsAutoConfigurationTests

Fixes #49572

[mhalbritter]

See #49572 (comment).