test: Add missing wait for version to be sent in add_outbound_p2p_connection #28822

Can be tested with:

diff --git a/test/functional/test_framework/p2p.py b/test/functional/test_framework/p2p.py
index b1ed97b794..eb4f72c6b6 100755
--- a/test/functional/test_framework/p2p.py
+++ b/test/functional/test_framework/p2p.py
@@ -205,6 +205,7 @@ class P2PConnection(asyncio.Protocol):
         assert not self._transport
         logger.debug("Connected & Listening: %s:%d" % (self.dstaddr, self.dstport))
         self._transport = transport
+        import time;time.sleep(.1);
         if self.on_connection_send_msg:
             self.send_message(self.on_connection_send_msg)
             self.on_connection_send_msg = None  # Never used again

Found and reported by mzumsande in #28782#pullrequestreview-1718560252

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