swipe-dismiss: isolate animation definition

- Isolate animation definitions from the WMShellBaseModule in order to
  allow build time override
- Consolidate animations under ShellBackAnimation class
- Move mAnimationDefinition into ShellBackAnimationRegistry to
  centralize operations on animation type
- Move animation initialization from ShellInit to injection time
- Other minor lint fixes

Test: build & flash on phone/watch
Test: atest com.android.wm.shell.back
Bug: 290801681
Bug: 290801423
Change-Id: I0a89a34e67f16ea861f2bc95ed49eb8e080450c2