ci: use restricted GITHUB_TOKEN istead of GITHUB PAT for issue state check

[pmalek]

What this PR does / why we need it:

Limit the scope of the GITHUB_TOKEN used in issue status check to issues read-only.
Ref: https://docs.github.com/en/actions/security-guides/automatic-token-authentication#permissions-for-the-github_token

Example workflow run: https://github.com/Kong/kubernetes-ingress-controller/actions/runs/6746666425

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (a364f35) 75.4% compared to head (c6122c9) 75.5%.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #5081     +/-   ##
=======================================
+ Coverage   75.4%   75.5%   +0.1%     
=======================================
  Files        167     167             
  Lines      18911   18911             
=======================================
+ Hits       14275   14294     +19     
+ Misses      3806    3792     -14     
+ Partials     830     825      -5     

see 6 files with indirect coverage changes

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