Instrumentation: Wait for finish when injecting pointer events

The input injection mode for pointer events in sendPointerSync() was
accidentally changed to WAIT_FOR_RESULT instead of WAIT_FOR_FINISH in
ag/17506923, causing test failures. Change it back to WAIT_FOR_FINISH.

Bug: 228203157
Bug: 228201593
Test: atest HoverTest
Change-Id: I2d3a77621290509d5be6279ee450e1881bd9d84d