_check_ingress_dispatch_stall is only called from the async polling
heartbeat, where a running loop always exists; the try/except RuntimeError
and the debounce reset that made its deferred retry work existed only for a
sync unit-test call. Match the sibling _check_polling_stall (no guard) and
delete the no-loop test. Without the fallback the counter stays at the
threshold until dispatch progresses, so a stall is escalated once.
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