We don't rely on FooterPreferenceMixinCompat
to create footer preference in dashboard fragment.
Instead, declare a FooterPreference explicitly in
xml of screen.
It makes more sense for our referenceController design.
Test: visual, robotest
Bug: 124129485
Change-Id: I0b0c0f9e38d85aa89b815ce2b84ddff30a1d206b
24c3324268