restore copying plugin metadata

Author: rjernst

build-tools/src/main/java/org/elasticsearch/gradle/plugin/BasePluginBuildPlugin.java

@@ -183,6 +183,7 @@ private static CopySpec createBundleSpec(
     ) {
         var bundleSpec = project.copySpec();
         bundleSpec.from(buildProperties);
+        bundleSpec.from(pluginMetadata);
         bundleSpec.from(
             (Callable<TaskProvider<Task>>) () -> project.getPluginManager().hasPlugin("com.gradleup.shadow")
                 ? project.getTasks().named("shadowJar")