Make call screening service bind like a top app

Call screening is part of the flow to get an incoming call
thus latency is crucially important. It was being bound with
default priority so this patch boosts it to schedule like a
top app as it will eventually end up in dialer app as a top
priority anyway and it is fully visible latency sensitive CUJ.

Bug: 242075837
Test: Trace analysis
Test: atest CallScreeningServiceFilterTest
Change-Id: Ia73981ee4a35e9d52a88e13375aa88d983cdd6a9
Merged-In: Ia73981ee4a35e9d52a88e13375aa88d983cdd6a9