ci(size-limit): Run size-limit action on node24 (#24308)

Bumps the `size-limit-gh-action` JS action runtime from `node20` to
`node24`.

The `node20` action runtime is deprecated on GitHub Actions runners, so
the action now executes `index.mjs` under Node 24, which current runners
support natively.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: mydea

dev-packages/size-limit-gh-action/action.yml

@@ -13,5 +13,5 @@ inputs:
     default: '0.0125'
     description: 'The percentage threshold for size changes before posting a comment'
 runs:
-  using: 'node20'
+  using: 'node24'
   main: 'index.mjs'