Consolidate configuraton dispatching logic

Introduce ConfigurationDispatcher to consolidate config dispatching
logic of WindowContext and WindowProviderService. This makes us easier
to adopt the configuration dispatching via WindowContextInfoItem.

Bug: 384428048
Test: atest WindowContextTests WindowContextPolicyTests
Test: atest FrameworksCoreTests:WindowContextTest FrameworksCoreTests:ContextTest
Test: atest ConfigurationDispatcherTest
Flag: EXEMPT refactor only

Change-Id: Ib400455e9442f1240ed6896ae5883f61b976bfc0