Ambiguous security permissions

[richardlau]

Follow on from #3176 (comment):

One of the things we need to now address is that version 3 of the Matrix Authorization Strategy plugin now requires permissions to be declared as for groups or users otherwise they are marked as ambiguous. A list of jobs that need to be updated can be found at https://ci.nodejs.org/administrativeMonitor/org.jenkinsci.plugins.matrixauth.AmbiguityMonitor/.

Fortunately the remediation is fairly simple but we need to do it for every job listed. As an example, for
node-test-pull-request, go into the "Configure" tab for the job and you'll see this:

The rows in orange with a ⚠️ symbol are the ambiguous ones. On the far right of the row, after the red cross, are two icons -- one for mitigating the entry as a user, and the other for mitigating as a group. For almost all of these I expect we'd be mitigating as a group (these should reflect GitHub groups as we are using GitHub Authentication).

[targos]

All jobs updated.