InputManagerService: Add proto logs for input stream modifications

Create a new proto log group and add logs for all requests coming into
InputManagerService to modify an input gesture stream.

Also, clean up unused pilferPointers method.

Bug: 418194047
Test: Presubmit
Flag: EXEMPT logging only
Change-Id: Ia0d0460f90025a17b76a83c599d40d96e6e8f486