Menu should auto-close at view-width < 1280 px

[chadwhitacre]

Steps to Repro

1. Visit https://vanguard.getsentry.net/ with window width < 1280 px.
2. Click on menu hamburger.
3. Click any link, e.g., drafts.

Expected

Menu disappears so I can see drafts.

Actual

Menu doesn't disappear. I'm all like "Where are the drafts? 😩".

Notes

The behavior is the same for all links on the menu (category, post, user). Manually closing the menu by clicking the "x" reveals the expected content underneath. The nav works, in other words. The bug is that the menu doesn't auto-close.