Add more comments for development mode

Author: kaibolay

firebase-appdistribution/src/main/java/com/google/firebase/appdistribution/impl/FeedbackActivity.java

@@ -46,7 +46,7 @@ public class FeedbackActivity extends AppCompatActivity {
       "com.google.firebase.appdistribution.FeedbackActivity.SCREENSHOT_URI";
 
   private FeedbackSender feedbackSender;
-  private String releaseName;
+  @Nullable private String releaseName; // in development-mode the releaseName might be null
   private CharSequence infoText;
   @Nullable private Uri screenshotUri;
 
@@ -113,6 +113,7 @@ private Bitmap readScreenshot() {
 
   public void submitFeedback(View view) {
     if (releaseName == null) {
+      // Don't actually send feedback in development-mode
       Toast.makeText(this, R.string.feedback_no_release, Toast.LENGTH_LONG).show();
       finish();
       return;

firebase-appdistribution/src/main/java/com/google/firebase/appdistribution/impl/FirebaseAppDistributionImpl.java

@@ -397,6 +397,7 @@ private void doStartFeedback(CharSequence infoText, @Nullable Uri screenshotUri)
                     .onSuccessTask(
                         taskExecutor,
                         releaseName ->
+                            // in development-mode the releaseName might be null
                             launchFeedbackActivity(releaseName, infoText, screenshotUri)
                                 .addOnFailureListener(
                                     e -> {
@@ -417,6 +418,7 @@ private Task<Void> launchFeedbackActivity(
         activity -> {
           LogWrapper.getInstance().i("Launching feedback activity");
           Intent intent = new Intent(activity, FeedbackActivity.class);
+          // in development-mode the releaseName might be null
           intent.putExtra(FeedbackActivity.RELEASE_NAME_EXTRA_KEY, releaseName);
           intent.putExtra(FeedbackActivity.INFO_TEXT_EXTRA_KEY, infoText);
           if (screenshotUri != null) {