Fix generating both settings.gradle and settings.gradle.kts for plugins (flutter#181592)

Fixes flutter#181565
Fixes flutter#142685
this was a side effect from flutter#173993

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Author: AbdeMohlbi

packages/flutter_tools/templates/plugin_shared/android.tmpl/settings.gradle.tmpl

@@ -319,7 +319,6 @@
     "templates/plugin_shared/.metadata.tmpl",
     "templates/plugin_shared/analysis_options.yaml.tmpl",
     "templates/plugin_shared/android.tmpl/.gitignore",
-    "templates/plugin_shared/android.tmpl/settings.gradle.tmpl",
     "templates/plugin_shared/android.tmpl/src/main/AndroidManifest.xml.tmpl",
     "templates/plugin_shared/CHANGELOG.md.tmpl",
     "templates/plugin_shared/LICENSE.tmpl",

packages/flutter_tools/templates/template_manifest.json

@@ -2912,6 +2912,28 @@ void main() {
     overrides: {FeatureFlags: () => TestFeatureFlags(), Logger: () => logger},
   );
 
+  testUsingContext(
+    'plugin includes only setting.gradle.kts',
+    () async {
+      // Regression test for https://github.com/flutter/flutter/issues/181565.
+      final command = CreateCommand();
+      final CommandRunner<void> runner = createTestCommandRunner(command);
+
+      await runner.run(<String>[
+        'create',
+        '--no-pub',
+        '--template=plugin',
+        '--org=com.example',
+        '--platforms=android',
+        projectDir.path,
+      ]);
+
+      expect(projectDir.childDirectory('android').childFile('settings.gradle.kts'), exists);
+      expect(projectDir.childDirectory('android').childFile('settings.gradle'), isNot(exists));
+    },
+    overrides: {FeatureFlags: () => TestFeatureFlags(), Logger: () => logger},
+  );
+
   testUsingContext(
     'plugin includes native Swift unit tests',
     () async {