Fix NPE crash when opening the app info from shortcut suggestion

It occurs NPE in invoking refreshUi() of AppButtonsPreferenceController
when user fully install the instant app from google play and then
directly open app info from the shortcut suggestion in launcher.

Root cause:
AppButtonsPreferenceController.refreshUi() will be invoked when user
directly open app info from the shortcut suggestion in launcher. In
refreshUi(), we will update the information of button preference, but
the preferences will not be initialized if device existed an instant
version for the app.

Solution:
Check button preference and initial them if need in refreshUi().

Fixes: 137854835
Test: visual, robotests
Change-Id: Id5c3e53b9db2683cab970c10eace7925d889eea3