CI shard test_telegram_conflict.py timed out (140s) because the new
_polling_heartbeat_loop, started by connect(), busy-spun under those
tests: they monkeypatch asyncio.sleep to instant and pass a bot double
with no get_me(), so the probe raised AttributeError (swallowed) and the
loop re-entered immediately with no real pacing, starving the event loop.
Guard the loop to return when bot.get_me is not callable — a real PTB Bot
always exposes it, so this only triggers on a torn-down app or a test
double, where there is nothing to probe. Also cancel the heartbeat task in
the conflict tests that call connect() without disconnect(), matching the
production disconnect() teardown.
Verified: test_telegram_conflict.py now runs in ~4.5s; the 22
heartbeat/reconnect tests still pass; E2E confirms a hanging get_me still
fires the reconnect ladder while a missing get_me exits without spinning.
ce802e932c