Skip POM download in regression test

CI runners are intermittently getting HTTP 404 from Maven Central
for stable artifacts (also affects main). Pass version=null so
AddDependency does not invoke MavenPomDownloader. The bug under
test is about the recipe making no change at all when
libs.versions.toml is present on Gradle 9, so the dependency
version is incidental.

Author: timtebeek

rewrite-gradle/src/test/java/org/openrewrite/gradle/AddDependencyGradle9CatalogTest.java

@@ -29,8 +29,11 @@ class AddDependencyGradle9CatalogTest implements RewriteTest {
 
     @Override
     public void defaults(RecipeSpec spec) {
+        // version=null avoids triggering MavenPomDownloader; the bug was about the
+        // recipe not making any change at all when libs.versions.toml is present on
+        // Gradle 9, so the version itself is incidental.
         spec.recipe(new AddDependency(
-                "org.projectlombok", "lombok", "1.18.30",
+                "org.projectlombok", "lombok", null,
                 null, "compileOnly", null,
                 null, null, null, Boolean.TRUE
         ));
@@ -68,7 +71,7 @@ void gradle9_catalogPresent_addDependencyShouldEditBuildKts() {
                         }
 
                         dependencies {
-                            compileOnly("org.projectlombok:lombok:1.18.30")
+                            compileOnly("org.projectlombok:lombok")
                         }
                         """
                 )
@@ -107,7 +110,7 @@ void gradle8_catalogPresent_addDependencyEditsBuildKts() {
                         }
 
                         dependencies {
-                            compileOnly("org.projectlombok:lombok:1.18.30")
+                            compileOnly("org.projectlombok:lombok")
                         }
                         """
                 )