Settings: Phone force close when set viocemail in speed dial settings

-PhoneGlobals is instantiated only for primary users so check for
 attempts to bring up voice mail settings screen for non-primary users
-Don't create voice mail to avoice FC if not primary user.

Test: manual - voicemail functionality
Bug: 34869710
Change-Id: I1451499c1507cd615e082e69e25b476a11036075
diff --git a/res/values/strings.xml b/res/values/strings.xml
index ec7d761..9a3232b 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -95,6 +95,8 @@
     <string name="no_vm_number_msg">No voicemail number is stored on the SIM card.</string>
     <!-- Button label on the "Missing voicemail number" dialog -->
     <string name="add_vm_number_str">Add number</string>
+    <!--Toast in Call settings when asked to launch voicemail for a guest user -->
+    <string name="voice_number_setting_primary_user_only">Voice mail for Call settings can only be changed by the primary user.</string>
 
     <!-- Status message displayed on SIM PIN unlock panel -->
     <string name="puk_unlocked">Your SIM card has been unblocked. Your phone is unlocking\u2026</string>