fix: negative dx/dy in feOffset (#2515)

# Summary

While working on #2514 I've noticed that negative dx/dy were treated as
positive.

## Test Plan

Add FeOffset filter with negative dx/dy to an element. It should move
closer to upper left corner.

## Compatibility

| OS      | Implemented |
| ------- | :---------: |
| Android |    ✅      |

Author: jakex7

android/src/main/java/com/horcrux/svg/FeOffsetView.java

@@ -44,8 +44,10 @@ public Bitmap applyFilter(HashMap<String, Bitmap> resultsMap, Bitmap prevResult)
     float dy = this.mDy != null ? (float) this.relativeOnHeight(this.mDy) : 0;
     RectF frame = new RectF(0, 0, dx, dy);
     this.getSvgView().getCtm().mapRect(frame);
+    dx = frame.left < 0 ? frame.left : frame.width();
+    dy = frame.top < 0 ? frame.top : frame.height();
 
-    canvas.drawBitmap(source, frame.width(), frame.height(), null);
+    canvas.drawBitmap(source, dx, dy, null);
 
     return result;
   }