Make management.tracing.enabled are first-class property

This will allow metadata to be generated for it automatically.

Closes gh-31656

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/TracingProperties.java

@@ -30,6 +30,11 @@
 @ConfigurationProperties("management.tracing")
 public class TracingProperties {
 
+	/**
+	 * Whether auto-configuration of tracing is enabled.
+	 */
+	private boolean enabled = true;
+
 	/**
 	 * Sampling configuration.
 	 */
@@ -45,6 +50,14 @@ public class TracingProperties {
 	 */
 	private final Propagation propagation = new Propagation();
 
+	public boolean isEnabled() {
+		return this.enabled;
+	}
+
+	public void setEnabled(boolean enabled) {
+		this.enabled = enabled;
+	}
+
 	public Sampling getSampling() {
 		return this.sampling;
 	}