chore(ci): remove stable cpr

[Namchee]

Overview

Closes #124

This pull request removes the stable cpr.yml and completely relies on the self-test flow for testing and pull request validation.

[github-actions]

Pull Request Validation Report

This comment is automatically generated by Conventional PR

Whitelist Report

Whitelist	Active	Result
Pull request is a draft and should be ignored	✅	❌
Pull request is made by a whitelisted user and should be ignored	❌	❌
Pull request is submitted by a bot and should be ignored	✅	❌
Pull request is submitted by administrators and should be ignored	❌	❌

Result

Pull request does not satisfy any enabled whitelist criteria. Pull request will be validated.

Validation Report

Validation	Active	Result
All commits in this pull request has valid messages	❌	✅
Pull request does not introduce too many changes	❌	✅
Pull request has a valid title	✅	✅
Pull request has mentioned issues	✅	✅
Pull request has valid branch name	❌	✅
Pull request should have a non-empty body	✅	✅

Result

Pull request satisfies all enabled pull request rules.

_{Last Modified at 22 Nov 24 14:51 UTC}