Bug 1851698 - Update default maxEvents to 1

[rosahbruno]

Docs update mozilla/glean#2611

changelog

• set the default maxEvents number to 1
• update existing tests that rely on having more than 1 event
• update comments in pings.yaml

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
  • Documentation should be added to The Glean Book when making changes to Glean's user facing API
    • When changes to the Glean Book are necessary, link to the corresponding PR on the mozilla/glean repository
  • Documentation should be added to the Glean.js developer documentation when making internal code changes

[travis79]

This looks good to me, but you might want to update the Glean docs and note the difference here with Glean.js in the limits section of the EventMetric here: https://mozilla.github.io/glean/book/reference/metrics/event.html#limits

[rosahbruno]

@travis79
Good callout, I updated this in the other PR - mozilla/glean@9956a3f

[travis79]

Thanks for updating the docs!