lineage-sdk: Set drawable bounds in generateAlertColorFromDrawable()

*) Android docs say this is required.

*) Fixes generating alert color from oreo gmail app (and probably
   many others).

Change-Id: Iad9a8ea82531c1cf844fae5456fd998a4b486165

sdk/src/java/lineageos/util/ColorUtils.java

@@ -277,6 +277,7 @@ public class ColorUtils {
                                          Math.max(1, height),
                                          Bitmap.Config.ARGB_8888);
             Canvas canvas = new Canvas(bitmap);
+            drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
             drawable.draw(canvas);
         }