Landscape Bouncer cleanup

Making improvements consistent across landscape Pin, Pattern, and Password bouncers.

Bug: 293252410
Fixes: 293427037

Test: KeyguardPasswordViewControllerTest, PasswordBouncerFoldableUIScreenshotTest, PasswordBouncerLargeUIScreenshotTest, PasswordBouncerSmallUIScreenshotTest, PasswordBouncerFoldableScreen, PasswordBouncerLargeScreen, PasswordBouncerSmallScreen, KeyguardPinViewControllerTest, PinBouncerFoldableUIScreenshotTest, PinBouncerLargeUIScreenshotTest, PinBouncerSmallUIScreenshotTest, PinBouncerFoldableScreen, PinBouncerLargeScreen, PinBouncerSmallScreen, KeyguardPatternViewControllerTest, PatternBouncerFoldableUIScreenshotTest, PatternBouncerLargeUIScreenshotTest, PatternBouncerSmallUIScreenshotTest, PatternBouncerFoldableScreen, PatternBouncerLargeScreen, PatterndBouncerSmallScreen
Change-Id: I0eeaf60569e57d915c254d8d3ba891c5a4880caa