build(android): pin ndkVersion to 28.2.13676358 for CI compatibility

cybernova2 · cybernova2 · commit 730a93a965df · 2025-12-05T00:17:03.000+05:30
diff --git a/android/app/build.gradle b/android/app/build.gradle
@@ -21,7 +21,7 @@ try {
 
 android {
     namespace "com.zulip.flutter"
-
+    ndkVersion "28.2.13676358"
     compileSdkVersion flutter.compileSdkVersion
 
     compileOptions {
