Change prometheus port annotation to string

[Rulox]

Proposed changes

Fixed a bug on daemon-set/deployment manifests when using the prometheus.io/port annotation for NGINX and NGINX Plus. Port needs to be a string and it was incorrectly set as an int.

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• 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 master
• I will ensure my PR is targeting the master branch and pulling from my branch from my own fork

[pleshakov]

👍