Mark all descendants of Defs as seen after a draw

When adding clipping paths in a def and changing properties of that clipping path (or its descendants), redraw is triggered only once as updates are never marked as seen.
This change makes sure to call `markUpdateSeen` on all descendants of the Defs node on a `draw`.

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

@@ -25,5 +25,12 @@ public class RNSVGDefsShadowNode extends RNSVGDefinitionShadowNode {
                 return true;
             }
         });
+        traverseChildren(new NodeRunnable() {
+            public boolean run(RNSVGVirtualNode node) {
+                node.markUpdateSeen();
+                node.traverseChildren(this);
+                return true;
+            }
+        });
     }
 }