Wayland in particular sets surface_capabilities.currentExtent.width to
the special value 0xFFFFFFFF, which is valid per spec.
Fixes#98779
It may also fix misc issues when resizing on all platforms.
Superseedes PR #98780 , thanks to user tdaven for the original patch.
PR #98780 would break Android support as it did not account that width
and height might need to be swapped.
Replaced manual swap by Godot's SWAP(), which indicates intention much
easier.