Fix qs tile drawing in edit QS panel

The problem here was reuse:

1. Tile has a SlashState -> gets SlashDrawable
2. Reused tile has no SlashState -> doesn't know how to gracefully
remove the slash and draw regularly, so it gets a slash anyway.

Unrelated, but also fixed: turn off slash animations in QS edit panel

Fixes: 63160044
Test: runtest -x
frameworks/base/packages/SystemUI/tests/src/com/android/systemui/qs/SlashImageViewTest.java

Change-Id: I6841bfafcef0588d1ca63b3326dfee1a856618f3