fix: Properly support non-Java Bazel 8 projects in IntelliJ (#7006)

Previously, the condition to load rules_java was based on the "additional languages" field,
which led to issues as Java is always present in IntelliJ (unlike PyCharm).
This change modifies the condition to explicitly check if rules_java
is actually loaded in the project, ensuring proper handling of non-Java projects in IntelliJ.

base/src/com/google/idea/blaze/base/sync/aspects/strategy/SyncAspectTemplateProvider.java

@@ -77,7 +77,7 @@ private void prepareProjectAspect(Project project) throws SyncFailedException {
     final var templateAspects = AspectRepositoryProvider.findAspectTemplateDirectory()
             .orElseThrow(() -> new SyncFailedException("Couldn't find aspect template directory"));
 
-    writeJavaInfo(manager, realizedAspectsPath, templateAspects);
+    writeJavaInfo(manager, realizedAspectsPath, templateAspects, project);
     writeCodeGeneratorInfo(manager, project, realizedAspectsPath, templateAspects);
   }
 
@@ -106,25 +106,29 @@ private void writeCodeGeneratorInfo(
   }
 
   private void writeJavaInfo(
-      BlazeProjectDataManager manager,
-      Path realizedAspectsPath,
-      File templateAspects) throws SyncFailedException {
+          BlazeProjectDataManager manager,
+          Path realizedAspectsPath,
+          File templateAspects, Project project) throws SyncFailedException {
     var realizedFile = realizedAspectsPath.resolve(REALIZED_JAVA);
     var templateWriter = new TemplateWriter(templateAspects.toPath());
-    var templateVariableMap = getJavaStringStringMap(manager);
+    var templateVariableMap = getJavaStringStringMap(manager, project);
     if (!templateWriter.writeToFile(TEMPLATE_JAVA, realizedFile, templateVariableMap)) {
       throw new SyncFailedException("Could not create template for: " + REALIZED_JAVA);
     }
   }
 
-  private static @NotNull Map<String, String> getJavaStringStringMap(BlazeProjectDataManager manager) {
+  private static @NotNull Map<String, String> getJavaStringStringMap(BlazeProjectDataManager manager, Project project) throws SyncFailedException {
     var projectData = Optional.ofNullable(manager.getBlazeProjectData()); // It can be empty on intial sync. Fall back to no lauguage support
+    var blazeProjectData = BlazeProjectDataManager.getInstance(project).getBlazeProjectData();
     var activeLanguages = projectData.map(it -> it.getWorkspaceLanguageSettings().getActiveLanguages()).orElse(ImmutableSet.of());
+    var isJavaEnabled = activeLanguages.contains(LanguageClass.JAVA)
+            && blazeProjectData != null
+            && blazeProjectData.getExternalWorkspaceData().getByRepoName("rules_java") != null;
     var isAtLeastBazel8 = projectData.map(it -> it.getBlazeVersionData().bazelIsAtLeastVersion(8, 0, 0)).orElse(false);
-      return Map.of(
-              "bazel8OrAbove", isAtLeastBazel8 ? "true" : "false",
-              "isJavaEnabled", activeLanguages.contains(LanguageClass.JAVA) ? "true" : "false"
-      );
+    return Map.of(
+            "bazel8OrAbove", isAtLeastBazel8 ? "true" : "false",
+            "isJavaEnabled", isJavaEnabled ? "true" : "false"
+    );
   }
 
   private static List<String> ruleNamesForLanguageClass(LanguageClass languageClass, ProjectViewSet viewSet) {