Implement Font Scaling Quick Settings Tile (4/n)

Setup the dialog panel for font scaling
 - Slider: The number of steps in the slider refers to the values
   options for font scaling. Changing the progress of the seekbar will
   change the size of fonts including the ones on the dialog panel.
 - Title and Done button: Update font size when onConfigurationChanged.

Bug: 242326166
Test: Attach a video to the bug
Test: atest FontScalingDialogTest
Change-Id: I9004aa933ff1d8021f3087a015ebc23bb8724871