Audit: log 'warnings' from eventlogger even if audit is deemed a success

[peteski22]

Description

Within audit there exists an scenario where the eventlogger broker reports that audit was deemed a success (because it managed to successfully log to at least 1 sink node), but there were warnings (errors) that came back from other audit devices where audit failed.

We want to ensure that we capture these warnings in the server log so that they don't go missing because we managed to log to a single device.

This PR has ENT and CE components.

HashiCorp Checklist

• [ ] Labels: If this PR is the CE portion of an ENT change, and that ENT change is getting backported to N-2, use the new style backport/ent/x.x.x+ent labels instead of the old style backport/x.x.x labels.
• [ ] Labels: If this PR is a CE only change, it can only be backported to N, so use the normal backport/x.x.x label (there should be only 1).
• [ ] ENT Breakage: If this PR either 1) removes a public function OR 2) changes the signature of a public function, even if that change is in a CE file, double check that applying the patch for this PR to the ENT repo and running tests doesn't break any tests. Sometimes ENT only tests rely on public functions in CE files.
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