Only reinflate bouncer after rotation if flag enabled

Re-inflating on orientation change is now guarded by the unreleased flag "lockscreen.enable_landscape", b/293252410, so the behaviour is back to the usual when this flag is off.

New tests to cover this case.

Bug: 295603468
Test: PinBouncerLandscapeLayout, PinBouncerPortraitLayout, PinBouncerLargeLayout
Change-Id: Ida08cc6e5c022a457e0d603ab75424d563dc0538