Refactor Dependabot rebase workflow

[nev21]

Updated workflow to rebase Dependabot PRs using GitHub CLI.

[Copilot]

Pull request overview

This PR refactors the Dependabot PR rebase workflow to use GitHub CLI instead of the peter-evans/rebase action. The workflow now posts "@dependabot rebase" comments on Dependabot PRs to trigger rebases through Dependabot's native comment commands.

• Replaced peter-evans/rebase action with GitHub CLI-based approach
• Changed permissions from write access to pull-requests only
• Added checkout step and GitHub CLI installation

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.89%. Comparing base (7e4502b) to head (634c453).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #481   +/-   ##
=======================================
  Coverage   98.89%   98.89%           
=======================================
  Files         108      108           
  Lines        2981     2981           
  Branches      621      645   +24     
=======================================
  Hits         2948     2948           
  Misses         33       33           

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.