In apply_output_config, this sets output->{width,height} using the
values in the output box. Previously, they were being set using
wlr_output_transformed_resolution, which takes the width and height
from the wlr_output and just checks whether they should be swapped
based on the transform. This did not take into account the output's
scale. wlr_output_effective_resolution could be used instead, which
handles both transform and scale. However, the values in the output box
have already been processed by wlr_output_effective_resolution so they
can just be used directly
Brian Ashworth