Refactor CallScreeningService's internal structure

Use a single AIDL method and perform logic in Telecom instead of slicing
up the call response on the client side.

Also pass through the call response to the connection service.

Bug: 179412110
Test: atest ConnectionServiceTest CallScreeningServiceTest
Change-Id: I878c0ce34142da104dc0e2795487b03a6bdacb5f