[conf] Disable hinting when emboldening (#19904)

Hinting will be done before Embolden in freetype2,
but in such case, Embolden will get wrong result
on some glyph contours after applying hinting.
Actually, hinting should be done after embolden, but we can't
fix it in current freetype2. So as a workaround, just turn off
hinting if we want to do embolden.