Use remote target when fallback IME control isnt available.

Certain form factors may not have statusbar, which is the fallback
control target. Instead, use remote insets control target (system) to
control IME.

Bug: 148234093
Bug: 158122585
Test: atest MultiDisplaySecurityTests on ATV

Change-Id: I9d027d8a6f42e4bce2711b62789531768dfe4018