test: Fix intermittent issue in interface_rest.py

Author: MarcoFalke

test/functional/interface_rest.py

@@ -337,6 +337,9 @@ def run_test(self):
         assert_greater_than(json_obj['bytes'], 300)
 
         mempool_info = self.nodes[0].getmempoolinfo()
+        # pop unstable unbroadcastcount before check
+        for obj in [json_obj, mempool_info]:
+            obj.pop("unbroadcastcount")
         assert_equal(json_obj, mempool_info)
 
         # Check that there are our submitted transactions in the TX memory pool