The backup examples and e2e suites no longer set passwords. They read
the generated ones from <release>-credentials with jq, since a username
may contain a dot that jsonpath treats as a path step, and log in as an
application user after each restore, so a restore that leaves the
credentials unusable fails the run. The MariaDB run also checks that an
account created out of band on the source is absent from the copy. The
unreachable-target restore step asserts a terminal Failed attributed to
the recovery window, since the reason itself is best effort.
Signed-off-by: Alexey Artamonov <aleksei.artamonov@aenix.io>