Move Bounce key and Slow key Dialog to DialogFragment, dialog will not
be dismissed when screen rotate.
Bug: 390243451
Bug: 374037603
Flag: com.android.settings.keyboard.keyboard_and_touchpad_a11y_new_page_enabled
Test: atest
packages/apps/Settings/tests/robotests/src/com/android/settings/inputmethod/
Change-Id: Ide87dbf8214f411941114281e7a5e8c81f75bdd4
demo: https://screenshot.googleplex.com/7CPpfHvAixe9Awr.png
Add dialog for Slow keys, which have same set up with Bounce keys.
Move dialog logic to InputSettingPreferenceController, to reuse it from
slow keys controller.
Bug: 346949547
Test: atest SettingsRoboTests
Flag: com.android.settings.keyboard.keyboard_and_touchpad_a11y_new_page_enabled
Change-Id: Ia4d74fcf3f20ed68cb252503e88d99ea79eae291