Optimizes the Content Capture workflow by calling the service directly.

Initially, the ContentCaptureManager (in the app) was calling the
IContentCaptureManager (on system server) for everything, even to pass the
list of captured events, which caused 2 IPCs for each batch of events (i.e.,
from app to system_server, then from system_service to service).

This CL optimizes the workflow by getting rid of the "middle man" and sending
the events from the app to the service directly, which the system_server only
calling the service to notify when the view starts and finishes (and passing
the UID in the former so the servier can validate the sendEvents() calls).

Bug: 119220549
Test: atest CtsContentCaptureServiceTestCases

Change-Id: I6c08dccf755605320ac37cbc9424132e5455a594