Style panel with Material designs (3/n)

The following components are styled to follow Material designs in this
modification:
1. All image buttons for adjusting magnifier window size
   - The background for image buttons
   - The tint for image buttons
   The icon button will get a background color when it is selected and
   the background color will be cleared when "Edit mode" for the window
   is triggered.

Bug: 257272333
Test: manual - attach screenshots with the bug
Test: atest
SystemUITests:com.android.systemui.accessibility.WindowMagnificationSettingsTest
Change-Id: I300f88be6fb9cc9e4c4bc4eaa7f5bf0e2c124d58