message: tests: Add missing assert_equal import to p2p_add_connections.py
diff: from test_framework.p2p import P2PInterface
  from test_framework.test_framework import BitcoinTestFramework
  -from test_framework.util import check_node_connections
  +from test_framework.util import (
  + assert_equal,
  + check_node_connections,
  +)
  class P2PFeelerReceiver(P2PInterface):
  def on_version(self, message):
  