fix(appset): return error on invalid annotations (#13730)

[raxod502-plaid]

Closes #13730.

Basically, when we run into a fatal error while trying to manipulate annotations or labels, return that error, instead of silently ignoring it as described in the linked issue. For cases where we were already ignoring errors at a higher level, I kept ignoring them, but I tried to abort in cases where it is important for the returned value to be correct. Added unit tests to cover the error cases.

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[crenshaw-dev]

Thanks, @raxod502-plaid!

[raxod502-plaid]

Thank you!!