This (mostly) allows the CSD added in
https://github.com/zed-industries/zed/pull/11525 to work in X11. It's
still a bit buggy as it detects a second window drag right after the
first one finishes, but it's probably better to change the way window
drags are detected in the title bar itself (as that causes other
issues).

The CSD can be tested by changing the return value of
`should_render_window_controls` to true.

Also fixes F11 crashing.

Release Notes:

- N/A