To address IME service context's Resources / DisplayMetrics update
when switching IME window to another display after onConfigurationChange.

We use Context#createDisplayContext to create display specific context when
display changed, to ensure soft keyboard can re-layout with correct resources.

Bug: 126930163
Test: manual with AOSP IME as below steps:
     1) Settings > Developer options > enable "Simulated Display" & "Force desktop mode".
     2) Reboot device
     3) Launch app (i.e. Contacts) with bluetooth or usb mouse in Simulated display.
     4) Tap EditText on app to see see if IME window layout correctly on simulated display.
     5) Launch app (i.e Files) on primary display.
     6) Tap EditText on app to see if IME window layout correctly on primary display.

Change-Id: I0ed6a079af1ed90c75fee1d36d5ce3ef3c41f8ed