android: don't proxy enterPictureInPicture in JitsiMeetFragment

android/app/src/main/java/org/jitsi/meet/MainActivity.java

 
     @Override
     protected void onUserLeaveHint() {
-        getFragment().enterPictureInPicture();
+        getFragment().getJitsiView().enterPictureInPicture();
     }
 
     @Override

android/sdk/src/main/java/org/jitsi/meet/sdk/JitsiMeetFragment.java

 
         JitsiMeetActivityDelegate.onHostPause(getActivity());
     }
-
-    public void enterPictureInPicture() {
-        if (view != null) {
-            view.enterPictureInPicture();
-        }
-    }
 }