Address appdistro test bug

Author: rlazo

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

@@ -33,9 +33,9 @@ class FeedbackSender {
   static final String CONTENT_TYPE_PNG = "image/png";
 
   private static final String TAG = "FeedbackSender";
-  private static final String FILE_EXTENSION_JPG = ".jpg";
-  private static final String FILE_EXTENSION_JPEG = ".jpeg";
-  private static final String FILE_EXTENSION_PNG = ".png";
+  private static final String FILE_EXTENSION_JPG = "jpg";
+  private static final String FILE_EXTENSION_JPEG = "jpeg";
+  private static final String FILE_EXTENSION_PNG = "png";
   private static final String DEFAULT_FILENAME = "screenshot.png";
 
   private final ContentResolver contentResolver;

gradle/libs.versions.toml

@@ -64,7 +64,7 @@ protobufjavautil = "3.25.5"
 protoc = "3.25.5"
 quickcheck = "0.6"
 reactiveStreams = "1.0.4"
-robolectric = "4.12"
+robolectric = "4.15"
 runner = "1.0.2"
 rxandroid = "2.0.2"
 rxjava = "2.1.14"