Add custom seekbar for mouse keys acceleration

Create the UI for mouse keys accleration seekbar.
Will implement the logic in a follow up cl.

screenshots:
light mode: http://screen/7wCXoShFyuizs7D
dark mode: http://screen/B6YRZ6LJpToQbFk

Bug: 393566398
Test: verified ui on the test device
Flag: com.android.server.accessibility.enable_mouse_key_enhancement
Change-Id: I09fc620ca068e6313aac92312a50149eb1374413