Unpinned admin sidebar can remain expanded after cursor is moved out

[ybnd]

Describe the bug

Once in a while, the admin sidebar "sticks" in the expanded state after the cursor is moved out.

Steps to reproduce the behavior:

1. Log in for the admin sidebar to show up
2. Hover over the sidebar until it expands
3. Open at least one expandable menu section
4. Move the cursor out of the sidebar, but don't click anywhere so it doesn't lose focus
   • You'll see that the sidebar remains open
   • You can scroll the page and interact with other "hoverable" elements, and the sidebar will remain open
   • You can even move the cursor out of the browser window
5. Click anywhere
   • The sidebar will close

Expected behavior

There should be a general timeout to ensure the admin sidebar closes after a while once the cursor is moved out.