Fix renaming for Bluetooth devices when rotating to landscape

The bug here is that when renaming a Bluetooth device (either the local
adapter or a paired device), if you click on the text edit field of the
alert dialog and then rotate the screen, the text shown in the soft
input will disappear. Also it's a usability problem that you even needed
to click in the first place. This CL fixes both problems - now the soft
input will be shown immediately when the dialog comes up, and the
content doesn't disappear on rotation.

Change-Id: Id29d11c834bf98c01b5c1208159537a8fd36a64f
Fixes: 72551780
Test: make -j RunSettingsRoboTests
(cherry picked from commit 5a158752)