windows: Fix autohide taskbar dosen't automatically appear when Zed is maximized (#16806)

Closes #12313

This PR introduces the following improvements:
1. Fixed the issue where the auto-hide taskbar wouldn't automatically
appear when Zed is maximized.
2. Refactored the `WM_NCCALCSIZE` code, making it more human-readable.

Release Notes:

- Fixed auto-hide taskbar would refuse to show itself when `Zed` is
maximized on
Winodws([#12313](https://github.com/zed-industries/zed/issues/12313)).

---------

Co-authored-by: Mikayla Maki <mikayla@zed.dev>