Move SwipeAnimation into its own file

This CL simply moves SwipeAnimation to its own file, so that it can be
used by other gesture-based transitions like predictive back. This is a
pure move.

Bug: 353679003
Test: Existing tests
Flag: com.android.systemui.scene_container
Change-Id: I160b4a75a836604196bbb199a3f2c8f77f173c35
2 files changed