Do not format precompiled Groovy convention plugins (#1583)

Exclude precompiled [Convention Plugins](https://docs.gradle.org/9.3.1/userguide/implementing_gradle_plugins_convention.html) from formatting

Author: CRogers

gradle-palantir-java-format/src/main/java/com/palantir/javaformat/gradle/SpotlessInterop.java

@@ -58,6 +58,10 @@ public void execute(JavaExtension java) {
         java.targetExclude("**/src/generated*/**");
         java.targetExclude("**/generated_*src/**");
         java.targetExclude("**/generated_*Src/**");
+        // build/groovy-dsl-plugins contains Java wrapper classes for
+        // https://docs.gradle.org/9.3.1/userguide/implementing_gradle_plugins_convention.html
+        // and don't need to be formatted.
+        java.targetExclude("**/groovy-dsl-plugins/**");
         // This is configuration cache safe as happening afterEvaluate
         java.addStep(spotlessJavaFormatStep());
     }