hot_standby_delay: Reports wrongly OK if standby server is unable to receive WAL stream

[L4rS6]

If the standby server is unable to receive the WAL stream and the postgresql standby server gets restarted

postgres[123]: walreceiver FATAL:  could not receive data from WAL stream: ERROR:  requested WAL segment 123ABC has already been removed

then the check reports OK even if there is no replication active

POSTGRES_HOT_STANDBY_DELAY OK: DB "postgres" (host:localhost) 43172953448 and 0 seconds | time=0.08s replay_delay=43172953448;2048;4096 receive-delay=43174652600;2048;4096 time_delay=0;30;60

Without restarting the standby server the check correctly reports CRITICAL:

POSTGRES_HOT_STANDBY_DELAY CRITICAL: DB "postgres" (host:localhost) 42855064712 and 2866 seconds | time=0.08s replay_delay=42855064712;2048;4096 receive-delay=42855059928;2048;4096 time_delay=2866;30;60