Fix kubernetes_state avoid tags collision

[clamoriniere]

What does this PR do?

Avoid tags collision for the "namespace"

Motivation

What inspired you to submit this pull request?

Additional Notes

Anything else we should know when reviewing?

Review checklist (to be filled by reviewers)

• PR title must be written as a CHANGELOG entry (see why)
• Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• PR must have changelog/ and integration/ labels attached
• Feature or bugfix must have tests
• Git history must be clean
• If PR adds a configuration option, it must be added to the configuration file.

[codecov]

Codecov Report

Merging #4149 into master will decrease coverage by 3.9%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #4149      +/-   ##
==========================================
- Coverage   86.71%   82.81%   -3.91%     
==========================================
  Files         743        4     -739     
  Lines       39233      384   -38849     
  Branches     4677       76    -4601     
==========================================
- Hits        34020      318   -33702     
+ Misses       3942       45    -3897     
+ Partials     1271       21    -1250

[hkaj]

Is it ever a problem? The problem is that namespace is generic and may end up conflicting with a host tag, or a tag from the cloud provider.

[clamoriniere]

@hkaj
we already use the kube_namespace tag for knowing on which kubernetes namespace the ksm pod is running.
So at least we do not conflict with one of our internal tag