swipe-dismiss: use original context for theme check

- For legacy windowSwipeToDismiss resolution, use the original context
  instead of base context. (Wear-specific compat behavior)
- Dialog uses a ContextWrapper that introduces additional theming.
  The base context would not correctly reflect the value for the window.

Test: atest ClockworkSystemUI
Bug: 294170826
Change-Id: I8a3098266d03b1de18925367ae281f72db3a61a1