test: explicit imports from test_framework.messages in p2p_invalid_messages.py

Summary:
This is a backport of Core PR18764 [3/3]
https://github.com/bitcoin/bitcoin/pull/18764/commits/4a614ff88ac71d6457513a4f7aa8a3235874ff3f

Depends on D9142

Test Plan: test/functional/test_runner.py p2p_invalid_messages

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D9143