Fix loading of the default animation settings

The animation settings were moved to global from system. So it
should be read by loadGlobalSettings() not loadSystemSettings().

This change fixes the resource overlaying of "def_window_animation_scale"
and "def_window_transition_scale".

Bug: 62524410
Test: FDR and run adb shell cat /data/system/users/0/settings_global.xml | \
      grep window_animation_scale
Change-Id: Ifafddbad3183fd6c2efca30c6b790f6ed6a95832