Fix inconsistent metric labels

[aledbf]

Which issue this PR fixes: fixes #2800

[codecov-io]

Codecov Report

Merging #2859 into master will increase coverage by 0.28%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #2859      +/-   ##
==========================================
+ Coverage   47.41%   47.69%   +0.28%     
==========================================
  Files          75       75              
  Lines        5433     5434       +1     
==========================================
+ Hits         2576     2592      +16     
+ Misses       2530     2512      -18     
- Partials      327      330       +3

Impacted Files	Coverage Δ
internal/ingress/metric/collectors/controller.go	90.67% <100%> (+13.75%)	⬆️
internal/watch/file_watcher.go	80.76% <0%> (-3.85%)	⬇️

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[antoineco]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aledbf, antoineco

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