Always run Actuator documentation tests

The tests must run so that the snippets included in the docs are
generated.

Closes gh-35875

buildSrc/src/main/java/org/springframework/boot/build/JavaConventions.java

@@ -186,6 +186,8 @@ class JavaConventions {
 			PredictiveTestSelectionExtension predictiveTestSelection = test.getExtensions()
 				.getByType(PredictiveTestSelectionExtension.class);
 			predictiveTestSelection.getEnabled().set(true);
+			predictiveTestSelection.mustRun((mustRun) -> mustRun.getIncludeClasses()
+				.add("org.springframework.boot.actuate.autoconfigure.endpoint.web.documentation.*"));
 		}
 	}