chore: enable thelper linter

[mmorel-35]

Description

enables and fixes thelper linter issues.

Notice that only naming rules are activated here.

[codecov]

Codecov Report

Attention: Patch coverage is 68.00000% with 8 lines in your changes missing coverage. Please review.

Project coverage is 68.93%. Comparing base (53d44f0) to head (1adb9d7).
Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
server/storage/wal/testing/waltesting.go	46.66%	8 Missing ⚠️

Additional details and impacted files

Files with missing lines	Coverage Δ
server/storage/backend/testing/betesting.go	87.50% <100.00%> (ø)
server/storage/wal/testing/waltesting.go	60.86% <46.66%> (ø)

... and 24 files with indirect coverage changes

@@            Coverage Diff             @@
##             main   #19271      +/-   ##
==========================================
- Coverage   68.97%   68.93%   -0.05%     
==========================================
  Files         420      420              
  Lines       35764    35764              
==========================================
- Hits        24670    24654      -16     
- Misses       9669     9687      +18     
+ Partials     1425     1423       -2     

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 53d44f0...1adb9d7. Read the comment docs.

[ahrtr]

Please rebase this PR, thx

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ahrtr, mmorel-35

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [ahrtr]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[mmorel-35]

/test pull-etcd-integration-1-cpu-amd64