Devops: Update GitHub Actions to use Node.js 24

[daidahao]

Checklist before merging this PR:

• Mentioned all issues that this PR fixes or addresses.
• Summarized the updates of this PR under Summary.
• Added an entry under Unreleased in the Changelog.

Fixes #.

Summary

Update GitHub Actions to use Node.js 24 runtime as Node.js 20 has reached end-of-life.

Currently, a lot of Darts CI rely on actions that are running on Node.js 20, which has reached EOL and will be removed from GitHub starting June 2nd, 2026. See darts PR merge workflow log for a recent example.

This PR tried to find and update all actions that rely on Node.js 20 to newer versions that rely on at least Node.js 24.

Other Information

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.24%. Comparing base (3095a02) to head (aeb5ae2).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3105      +/-   ##
==========================================
- Coverage   96.31%   96.24%   -0.07%     
==========================================
  Files         161      161              
  Lines       17350    17350              
==========================================
- Hits        16710    16699      -11     
- Misses        640      651      +11     

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[dennisbader]

Thanks a lot @daidahao 🚀

Looks good to me :) Can you update the PR number in the changelog? Then we can merge 💯