Dialer: Video call icon not sync with the setting in call.

The field name to retrieve is wrong and the listener
registered is unreasonable which uses for giving the
client a chance to prevent setting and/or persisting
the new value. Using OnPreferenceClick is more
suitable.

Change-Id: I26ba246948dc27b492e7de437dc00414885894b5
CRs-fixed: 1058633