[EXPD] Make non-collapsible toolbar style customizable

Setting Theme.CollapsingToolbar.Settings (which inherits from
Theme.MaterialComponents) as android:theme on AppBarLayout overrides
almost all the theme attributes from the original OEM customizable
Theme.DeviceDefault.Settings theme, because Theme.MaterialComponents
eventually inherits from android:Theme.Material which resets everything.

This change creates a PlatformBridge theme overlay that allows adding
the required theme attributes for MaterialComponents to work, without
resetting everything and make child views deviate from the intended
platform theme.

An OEM will be able to set android:toolbarStyle to customize the action
bar after this change, which is the intended way for customization.

The new theme overlay is only used for the OEM-only
non_collapsing_toolbar_content_layout.xml for now, so that there's no
risk of regression on AOSP or Pixel builds.

Bug: 349675008
Test: atest CtsPermissionUiTestCases
Flag: com.android.permission.flags.app_permission_fragment_uses_preferences
Relnote: N/A
Change-Id: I106c07680ccd4514f888506117c165a5764f1ce5