[CP] Adjust chroma/lstar filters for seed colors

There is a set of wallpapers, namely some Landscape wallpapers, that
don’t have any colors extracted from them. The wallpaper visually has
some color to it, but, the chroma of those colors is low enough that
they get filtered out by the low chroma filter.

Lower the chroma filter from 15 to 5, and eliminate the tone filter
(previously, L >= 10). Scoring compensates for this by prioritizing
chromatic colors, thus ensuring these low-chroma options are only used
if there’s no better options.

Bug: b/200675148
Test: Push landscape wallpapers #912, #914, and #924 from Monet
Studio to device. Verify color choices reflect wallpaper and aren't just
fallback colors.

Change-Id: I080e6cb51978638462a8b0ab41340aa11d495c93