Remove redundant Prometheus variable labels (#5008)

[haywoodsh]

Remove redundant variable labels

Signed-off-by: Haywood Shannon 5781935+haywoodsh@users.noreply.github.com
(cherry picked from commit fb60fb6)

Proposed changes

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that issue here in this description (not in the title of the PR).

Checklist

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• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (997981f) 52.16% compared to head (c0dc07c) 52.18%.

Files	Patch %	Lines
cmd/nginx-ingress/main.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@               Coverage Diff               @@
##           release-3.4    #5085      +/-   ##
===============================================
+ Coverage        52.16%   52.18%   +0.01%     
===============================================
  Files               60       60              
  Lines            17368    17366       -2     
===============================================
+ Hits              9060     9062       +2     
+ Misses            7994     7990       -4     
  Partials           314      314              

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