[Contextual Edu] Customize education dialog

Customize the dialog according to Figma:
https://www.figma.com/design/ccBEWEnusF6lE4edgCw7bG/Android-Interactions-Library?node-id=12526-438003&t=SZOfJE3ThnLfVd7Y-1

Testing result: https://screenshot.googleplex.com/AkRqioF5x3UUQYp

Bug: 369791926
Test: trigger the dialog and check if the dialog is displayed as expected, will add screenshot test in b/370908143
Flag: com.android.systemui.keyboard_touchpad_contextual_education

Change-Id: Ia130e06a39a02c9a0d18fb50a3239c1cfc62a842