CI: Don't fail on expected critical log messages

There is a number of critical log messages that we see in CI from time
to time. While these should be fixed, let's not fail jobs unnecessarily.

This change introduces one expected critical message in
placement-api.log:

    Failed to fetch token data from identity server

Co-authored-by: Radosław Piliszek <radoslaw.piliszek@gmail.com>
Related-bug: #1847727
Change-Id: I92ad0be70ed05925612f0c709907ab62280326b8