update @babel/runtime to not be a pinned specific version

[mansona]

This PR will remove the vulnerability report from ember-cli-babel, or at least we could easily fix it in a follow up PR 👍

Edit: it seems that the floating dependency issue has nothing to do with this PR 🤔 it looks like it's related to execa

[NullVoxPopuli]

floating deps are red

- errorMessage: require() of ES Module 
  /home/runner/work/ember-cli-babel/ember-cli-babel/node_modules/.pnpm/execa@9.6.1/node_modules/execa/index.js 
  from /home/runner/work/ember-cli-babel/ember-cli-babel/node_modules/.pnpm/testem@3.20.1_@babel+core@7.29.7/node_modules/testem/lib/utils/fileutils.js 
  not supported.

Instead change the require of index.js in /home/runner/work/ember-cli-babel/ember-cli-babel/node_modules/.pnpm/testem@3.20.1_@babel+core@7.29.7/node_modules/testem/lib/utils/fileutils.js 
to a dynamic import() which is available in all CommonJS modules.

so, floating deps ci needs a node upgrade+?
(is that breaking for this package? I don't know if the node policy is the same as the ember-proper libraries)

[mansona]

this is just a bug in testem where they merged a breaking change as a minor, I tried to tell them that they shouldn't do that but the discussion thread was locked and the main maintainer was not for listening any more

[mansona]

If we merge this then all the floating deps CI jobs start working again: #539