Identify source of invalid crumb starting 6fc027348 and remediate

[sxa]

We're getting one of these every five seconds in the jenkins system log and it's certainly been going for a few days and producing one of these roughly every five seconds and is accounting for about 25% of the lines in the log:

2024-03-19 22:59:27.813+0000 [id=1216288] WARNING hudson.security.csrf.CrumbFilter#doFilter: Found invalid crumb 6fc027348e106dfb4ce52f6fbfc63c74dcae604f2e24e1efb46470f318326a67. If you are calling this URL with a script, please use the API Token instead. More information: https://www.jenkins.io/redirect/crumb-cannot-be-used-for-script

We should identify the source of it and clean it up. It could just be someone's expired session.

[sxa]

Looks to be a session of @steelhead31 's relating to the test-docker-sles12-s390x-1 machine.

[steelhead31]

Think I've resolved this, a cached webpage I believe, in a crashed browser session, that wasn't visible
anywhere...

[steelhead31]

Resolved.

[sxa]

Noting that the sensible string to check for if we want to identify this in the future is:
WARNING hudson.security.csrf.CrumbFilter#doFilter: No valid crumb was included in request for <jenkins url path> by <username>. Returning 403.
Searching for CrumbFilter.*403 works quite well.