Improve IMF visibility log (3/N)

Add event logs for IME animation process
to debug when flicker or visibility issues
happened. These logs record insets, alpha,
animation type and use ImeTracker.Token's tag
for identification.

The log is only enabled for debug builds.

Bug: 239501597
Test: presubmiti
Change-Id: I70c60b4a46373dfdebb92952ea34ce81eacad0bb