Ignore time-advancing message in mediator off-boarding log [static] (#2670)

Fixes DACH-NY/cn-test-failures#5899

Signed-off-by: fayi-da <[email protected]>

Author: fayi-da

project/ignore-patterns/canton-standalone-mediator-offboarding.ignore.txt

@@ -12,3 +12,5 @@ INCORRECT_EVENT_COST.*: Missing or incorrect event cost provided by member
 TOPOLOGY_UNAUTHORIZED_TRANSACTION
 
 Failed to send result to sequencer for request.*Unregistered recipients.*unregistered senders.*MED::sv4SvOffboarding
+
+Could not send a time-advancing message