Further compress the recovery animation file

The res/images/loop.*png can be further compressed with "pngquant
--quality 0-10"; and the difference is not noticeable to humans
under recovery. And This reduces the animation pictures under res-xxxhdpi
from 2.7M to 1.2M.

Note that the *_text.png files can't be compressed this way because they
requires lossless compression to keep the embedded locales intact.

Bug: 112494634
Test: Run recovery graphic tests.
Change-Id: I2cefaea8e037cb09cb4e4735d1b86e82da9e6875