Fix initial iteration in DefaultImeVisibilityTest

Ensure rotation is successfully applied before starting the stress test
iterations, as this would previously lead to the first iteration of the
landscape test still being in portrait mode, and incorrectly passing the
assertions.

Test: atest DefaultImeVisibilityTest
Bug: 291742721
Change-Id: Iae068a92601d6dc632f10373ab6ab4bd41dd742d