chore: rm pr template checkboxes covered by CI

[mmkal]

Summary

My opinion: there's no need for these three checkboxes:

• [ ] Code is formatted via running yarn format.
• [ ] Tests are passing via running yarn test.
• [ ] The status checks are successful (continuous integration). Those can be seen below.

The CI checks can run yarn format and yarn test, and the status checks speak for themselves. CI creates a ✅ , there's no need to ask a human to do it too. (plus, the status checks usually can't be successful when the PR is first created, since it's the PR that triggers them in the first place, so the question doesn't really make sense.

Test plan

N/A

Checklist

Please add a x inside each checkbox:

• [X] I have read the contribution guidelines.

A picture of a cute animal (not mandatory but encouraged)

(credit: DALL-E 2)