Update MotionEvent's id when a new sample is added.

Until now the MotionEvent's id was set during the "initialize" call, and it was equal to the first sample's eventId. We want to use the latest sample's eventId.

Bug: b/350907221
Test: atest libinput_tests inputflinger_tests
Flag: EXEMPT bugfix

Change-Id: I0d967e7fe644fc2b2c09d044c3ee8ed13276d787
7 files changed