Restrict trigger push branch for GitHub Workflow

[apupier]

Feature branches rarely need their own CI runs: the code is already tested when a pull request is opened against a release branch. If the push trigger has no branch restriction and pull_request is also configured, every push to a branch with an open PR runs the workflow twice: once for the push and once for the PR synchronisation.

Always give the push trigger an explicit list of branches: this stops branches created from a release branch from inheriting its workflow runs.

see https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=430408443#GitHubActionsRecommendedPractices-Restrictthepushtriggertospecificbranches

Description

This PR...

Types of changes

• Breaking change (fix or feature that would cause existing functionality to change)
• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Enhancement (improves an existing feature and functionality)
• Cleanup (Code refactoring and cleanup, that may add test cases)
• Build/CI
• Test (unit or integration test code)

Feature/Enhancement Scale or Bug Severity

Feature/Enhancement Scale

• Major
• Minor

Bug Severity

• BLOCKER
• Critical
• Major
• Minor
• Trivial

Screenshots (if appropriate):

How Has This Been Tested?

How did you try to break this feature and the system with this change?

[boring-cyborg]

Congratulations on your first Pull Request and welcome to the Apache CloudStack community! If you have any issues or are unsure about any anything please check our Contribution Guide (https://github.com/apache/cloudstack/blob/main/CONTRIBUTING.md)
Here are some useful points:

• In case of a new feature add useful documentation (raise doc PR at https://github.com/apache/cloudstack-documentation)
• Be patient and persistent. It might take some time to get a review or get the final approval from the committers.
• Pay attention to the quality of your code, ensure tests are passing and your PR doesn't have conflicts.
• Please follow ASF Code of Conduct for all communication including (but not limited to) comments on Pull Requests, Issues, Mailing list and Slack.
• Be sure to read the CloudStack Coding Conventions.
  Apache CloudStack is a community-driven project and together we are making it better 🚀.
  In case of doubts contact the developers at:
  Mailing List: dev@cloudstack.apache.org (https://cloudstack.apache.org/mailing-lists.html)
  Slack: https://apachecloudstack.slack.com/

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 18.93%. Comparing base (a97c510) to head (e82429c).

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #13522      +/-   ##
============================================
- Coverage     18.93%   18.93%   -0.01%     
- Complexity    18471    18474       +3     
============================================
  Files          6221     6221              
  Lines        560048   560048              
  Branches      68290    68290              
============================================
- Hits         106068   106056      -12     
- Misses       442351   442368      +17     
+ Partials      11629    11624       -5     

Flag	Coverage Δ
uitests	3.50% <ø> (ø)
unittests	20.14% <ø> (-0.01%)	⬇️

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[apupier]

sonar erro is unrelated to this PR:

POST /repos/apache/cloudstack/issues/13522/comments - 403 with id A818:34F90C:762457:780104:6A451A2F in 365ms
RequestError [HttpError]: Resource not accessible by integration - https://docs.github.com/rest/issues/comments#create-an-issue-comment
    at fetchWrapper (/home/runner/work/_actions/actions/github-script/3a2844b7e9c422d3c10d287c895573f7108da1b3/dist/index.js:61509:11)
Error: Unhandled error: HttpError: Resource not accessible by integration - https://docs.github.com/rest/issues/comments#create-an-issue-comment
    at process.processTicksAndRejections (node:internal/process/task_queues:104:5)
    at async eval (eval at callAsyncFunction (/home/runner/work/_actions/actions/github-script/3a2844b7e9c422d3c10d287c895573f7108da1b3/dist/index.js:64949:16), <anonymous>:36:1)
    at async main (/home/runner/work/_actions/actions/github-script/3a2844b7e9c422d3c10d287c895573f7108da1b3/dist/index.js:65100:20) {
  status: 403,
  request: {
    method: 'POST',
    url: 'https://api.github.com/repos/apache/cloudstack/issues/13522/comments',
    headers: {
      accept: 'application/vnd.github.v3+json',
      'user-agent': 'actions/github-script actions_orchestration_id/1ab6608d-03a6-4789-9e51-f367e5e95cbe.build.__default octokit-core.js/7.0.6 Node.js/24',
      authorization: 'bearer [REDACTED]',
      'content-type': 'application/json; charset=utf-8'
    },
    body: [Object: null prototype] {
      body: '## 🔴 Test Coverage Grade: `D` — Marginal\n' +