Emscripten buildbot should run against node 24

[hoodmane]

We want to support pyrepl #124621 but it will require JSPI which requires node 24. So to test this we should run tests against node 24.

Linked PRs

• gh-136852: Emscripten: Add PYTHON_NODE_VERSION environment variable #136853
• [3.14] gh-136852: Emscripten: Add PYTHON_NODE_VERSION environment variable (GH-136853) #136907
• gh-136852: Emscripten: Fix bug in #136853 #136909

[StanFromIreland]

@picnixz Is this not better off moved to buildmaster-config, there is nothing to be done for this issue in this repo?

[hoodmane]

The linked pr changes this repository.