Fix not invoke setImeWindowStatus when unlocked by PIN lock

CL[1] removed setImeWindowStatatus call in showSoftInput()
since showWindow() has a call.

Howerver, the call invokes only when the IME visibility has changed.
It overlooked the case that when the screen unlocked by PIN
lock, since the focused app and IME visiblity is the same, so
the setImeWindowStatus in showWindow() doesn't invoked.

When then keyguard shown, IMMS side will invoke updateSystemUiLocked to
update navbar icon as invisible, so after the user unlocked, user won't
see the navbar icon set visible back.

As the result, we still need setImeWindowStatus called in showSoftInput
to fix this case.

[1]: I0b0750f146634d8e90e0b0ac46e9208675626d0a

Fix: 181294561
Test: manual as below steps:
  0) setup PIN lock for the device
  1) launch an app (e.g. Messaging) and show IME
  2) turn-off the screen and unlock the screen with PIN
  3) verify if the keyboard is visible and the navbar icon is visible
Change-Id: I168fda76c1c7bdcabe94f7c2550c6b5c7c41e5e0