Fix SettingsProvider for use_resource_processor: true

Compile the SettingsProvider sources and resources once in an
android_library instead of separately in SettingsProvider and
SettingsProviderTest so that the resources are only compiled with
one package name and can always be referenced via that package.

Bug: 294256649
Test: m javac-check
Change-Id: I085c45b130ff1d2fc2726d2b9ecd237abe1db033