Add symmetric Getters to PictureInPictureParams

- Adds getter to all setters in PictureInPictureParams.Builder
- Changes getAspectRatio and getExpandedAspect ratio to return the
  Rational values instead of floats to ensure symmetry

Bug: 220740459
Test: atest PictureInPictureParamsTest#testPictureInPictureParamsGetters
Test: atest PictureInPictureParamsTest#testPictureInPictureParamsGettersNullValues
Test: atest PinnedStackTests#testFillMaxAllowedActions
Test: atest PinnedStackTests#testRejectExceededActions
Test: atest PinnedStackTests#testCloseActionIsSet
Test: atest PinnedStackTests#testTitleIsSet
Test: atest PinnedStackTests#testSubtitleIsSet
Test: atest PinnedStackTests#testIsSeamlessResizeEnabledDefaultToTrue
Test: atest PinnedStackTests#testDisableIsSeamlessResizeEnabled

Change-Id: Idb06fbf326815181c3e43907dc9c47e5ecc125d0