Previously, fractional scaling was detected but set an integer buffer
scale which the compositor would down-scale causing blurry output.
Now the fractional scaling interface is used when available to set the
DPI and set the internal buffers size & viewport transformation to
ensure 1:1 pixels from Blender to the Wayland output.
Tested to work with multiple monitors with mixed
fractional/non-fractional scale.
Note that this change causes a regression for when fractional scaling
is set on a compositor without support for fractional-scale-v1.
Supporting fractional scaling in both cases is possible but overly
complicated. This case already wasn't working so well - with blurry
output due to image scaling, now the DPI wont be accurate in this case
although Blender is still usable.
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