Bug 1693487 - Accept booleans and numbers as event extras

[brizental]

Pull Request checklist

• Quality: Make sure this PR builds and runs cleanly.
  • Inside the glean/ folder, run:
    • npm run test Runs all tests
    • npm run lint Runs all linters
• Tests: This PR includes thorough tests or an explanation of why it does not
• Changelog: This PR includes a changelog entry to CHANGELOG.md or an explanation of why it does not need one
• Documentation: This PR includes documentation changes, an explanation of why it does not need that or a follow-up bug has been filed to do that work
  • This behaviour is already documented on the Glean book, although looking at the docs I think they might benefit from having examples for quantity and boolean extra types too. I'll follow-up with a PR to the Glean book updating it.

Opening as a draft: I'll make the necessary changes to glean_parser and then update glean_parser in this PR before it is ready.

[brizental]

This with the glean_parser update is pretty neat. See: