caos.backends.pgsql: Always issue link mapping update when a concrete link is removed
caos.backends.pgsql: Always issue link mapping update when a concrete link is removed

Issue link mapping update when a concrete link is removed, whether it's
atomic or not.  This should fix the potential loss of sync between
mapping indexes and the schema.

edgedb/edgedb,edgedb/edgedb,edgedb/edgedb