Metrics exporter cache requests that fail with an unrecoverable error

[avilevy18]

Fixes #765

When the metrics exporter fails to create a new metric descriptor any non-recoverable grpc errors will update the cache, preventing further CMD calls.

[codecov[bot]]

Codecov Report

Merging #768 (64af3e9) into main (0b578e8) will increase coverage by 0.33%. Report is 2 commits behind head on main. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #768      +/-   ##
==========================================
+ Coverage   69.52%   69.85%   +0.33%     
==========================================
  Files          42       42              
  Lines        4859     4863       +4     
==========================================
+ Hits         3378     3397      +19     
+ Misses       1331     1315      -16     
- Partials      150      151       +1     

Files	Coverage Δ
exporter/collector/metrics.go	74.44% <100.00%> (+1.43%)	:arrow_up:

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[punya]

/gcbrun

[dashpole]

@avilevy18 I'm planning to cut a release later today. If you can add test coverage by then, then we can include it. Let me know if we can help direct you.

[dashpole]

/gcbrun

[dashpole]

you can run make fieldalignment to fix the error

[dashpole]

/gcbrun

[dashpole]

/gcbrun