Fix crash when operator name contains %

Currently, cannot use ListPreference.setSummary() when the summary
contains user generated string, because ListPreference.getSummary() is
using String.format() to format the summary when the summary is set by
ListPreference.setSummary().

Use preference.setSummaryProvider() instead, which is recommended for
ListPreference.

Fix: 233295254
Test: manual
Change-Id: Ia24d88817c99db7ed3fc264dbc9c10e0a09d8a39