Re-send the IME control after IME is re-created

The control would be revoked when setting window to the insets source
provider. So this CL updates the control target again after IME window
is set to the provider, and also refines the timing about updating IME
control target.

Fix: 152185205
Fix: 152698568
Fix: 153831557
Test: atest NexusLauncherTests:MemoryTests MultiDisplayClientTests
Test: 1. Add Traditional Chinese as a secondary language in Setitngs.
      2. Launch soft keyboard in Messages and use ZhuYin keyboard.
      3. Tap microphone icon repeatedly (this will re-create IME).
      4. See if the soft keyboard is missing.
Test: Also make sure b/149920295 and b/152410995 stay fixed.
Change-Id: Ic113f564e964ebb0ab3375cf1df78b3f912169da