Add APIs to hide voicemail settings.

With unbundle visual voicemail and dialer voicemail notification, the
dialer should be able to control the voicemail settings, and refer
telephony settings as "Advance settings" only showing the options
not in the public API.

This CL gives the default dialer the ability to hide duplicated
settings in telephony.

Bug: 34691905
Fixes 34691905
Test: CTS verifier test "hide public settings in voicemail"
      "hide voicemail in call settings"
Change-Id: I6589c3d77b5075265cf013ee56524a342904ecd1