Remove high quality glow as it is not any higher quality than regular glow

[clayjohn]

While working on #70003 I noticed that the high quality glow mode is actually no longer needed since we switched to this optimized compute shader-based glow. The low quality mode already samples all the pixels from the previous mip level. The high quality mode actually made the effect look worse and take 2X as long since it doubled the pixel samples, but just read the extra pixels from a fixed offset.

I originally tried to "fix" high quality mode, but there is no way to make it not broken its just needlessly taking extra samples.

Marked as breaking compatibility because users may be using the functions to set the quality manually. I would prefer to remove everything as I have, but if we want to avoid breaking compatibility, I can mark the setting and functions as deprecated and just make them do nothing.

"Low quality" mode

"High Quality" enabled: notice how the glow looks lopsided

These next images are pretty much worse case scenario for glow as they contain one pixel aliased lines. Capturing fine features like this was the reason we added the high quality mode in the first place.

"Low quality" mode

"High Quality" enabled: There is a very slight shift of strength to the upper left, but it is almost impossible to see without an image diff tool

[akien-mga]

Thanks!