[USSD] Consolidate USSD messages in a single dialog box

All USSD messages (interactive or non-interactive) will be displayed
in a single dialog-box with a separator in between messages.

Bug: 12892053

Change-Id: I31bc0cd4b55492e4e62adc8c925cc0371c54f5a8
diff --git a/res/values/strings.xml b/res/values/strings.xml
index 8e92006..47d066b 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -379,6 +379,10 @@
     <string name="roaming_reenable_message">You\'ve lost data connectivity because you left your home network with data roaming turned off.</string>
     <!-- Mobile network settings screen, dialog message when user selects the Data roaming check box -->
     <string name="roaming_warning">Allow data roaming? You may incur significant roaming charges!</string>
+
+    <!-- USSD aggregation dialog box: separator strings between messages (new-lines will be added before and after) -->
+    <string name="ussd_dialog_sep" translatable="false">----------</string>
+
     <string name="gsm_umts_options">GSM/UMTS Options</string>
     <string name="cdma_options">CDMA Options</string>