Cancel pre-existing PHASE_WM_SHOW_IME_RUNNER

This treats any pre-existing statsToken at PHASE_WM_SHOW_IME_RUNNER as
canceled instead of failed, and also adds a new
PHASE_WM_ABORT_SHOW_IME_POST_LAYOUT to tell this apart from
abortShowImePostLayout, where the request actually fails.

Test: show IME in launcher and check ImeTracker logs
Bug: 324053104
Change-Id: I810ac6b5f47eb3b6e104410d99ffc1cea87545db