Make the SearchDialog's AutoCompleteTextView dropdown respect the

IME again when the user presses right or left from a query-jammed
suggestion to continue editing. Previously we required the user
to press on the text field again in order to get the IME to show.

We accomplish this by factoring out the code to 'ensureImeVisible'
into a separate method and calling that from SearchDialog.

Fixes http://b/1976338