Fix branch name change when pressing Enter
This fixes a bug where the branch name could not be changed by pressing Enter after typing a new branch name in the BranchHeader's BranchLabel field.
I believe the issue is that the <input/> field is unmounted by setting inputActive = false in on:keydown before the on:change function can be executed.
Running inputActive = false asynchronously, as is already done for label.focus(), seems to fix the issue for me.
I realize there may be better ways to fix this, but this is all I had time for. I also added a comment to explain the change but feel free to edit or remove it if it doesn't fit your style.
Versions of GitButler and OS where this was reproduced and fixed:
macOS 14.2.1 (23C71).
GitButler Version 0.10.7 (20240213.214246).
GitButler master as of now.
Discussed (briefly) on Discord: https://discord.com/channels/1060193121130000425/1206670506271707156/1207405803661951036.