Remove logic for select input method preference.

- The prefrence is not used in code according to comment, and it's not
  defined in xml. So this chunk of code is redundant and should be
  removed.

Bug: 32642706
Test: compiles, and manually navigate to fragment.
Change-Id: Iac38632d090c635f324bc4eed8e1c41300ddb08e
1 file changed