Fix timeout created by most recent gtk-layer-shell release when creating bars for multiple monitors.

[Mervius]

Attempts to fix #4978

I do not think I am great at C++, so this might be terrible, but this appears to work fine. At the very least, if this is bad, it is an example of the base steps needed to fix the problem.

This first gathers all the monitor information before creating any bars rather than creating them each individually per each .done

[The-Ludwig]

Can confirm, this works for me on sway and fixes the issue!

[Mervius]

This might need testing for it it still interacts properly with monitor hotplugging, resizing, and position changes.
I think it should, but I'm not certain. hotplugging appears to work for me. I could in theory seem some weirdness if a monitor change happens twice in quick succession with the same monitor