make drawable mutable

Signed-off-by: tobiaskaminsky <tobias@kaminsky.me>

src/main/java/com/owncloud/android/ui/dialog/SendShareDialog.java

@@ -150,7 +150,7 @@ public class SendShareDialog extends BottomSheetDialogFragment {
 
     private void themeShareButtonImage(ImageView shareImageView) {
         shareImageView.getBackground().setColorFilter(ThemeUtils.elementColor(), PorterDuff.Mode.SRC_IN);
-        shareImageView.getDrawable().setColorFilter(ThemeUtils.fontColor(), PorterDuff.Mode.SRC_IN);
+        shareImageView.getDrawable().mutate().setColorFilter(ThemeUtils.fontColor(), PorterDuff.Mode.SRC_IN);
     }
 
     private void showResharingNotAllowedSnackbar() {