Divide by zero in WindowInfo::constrain_resize()

[AlanGriffiths]

The methods min_aspect() and max_aspect() can return AspectRatio{0U, std::numeric_limits<unsigned>::max()} and AspectRatio{std::numeric_limits<unsigned>::max(), 0U} respectively. But WindowInfo::constrain_resize() divides by both ar.height and ar.width without checking for 0:

Thread 1 "miral-shell.bin" received signal SIGFPE, Arithmetic exception.
0x00007b8821332135 in miral::WindowInfo::constrain_resize (this=0x7b87a808a9c0, requested_pos=..., requested_size=...) at /home/alan/CLionProjects/mir/src/miral/window_info.cpp:229
229	            auto const width_correction  = (error+(ar.height-1))/ar.height;