Enable external call support in AOSP dialer manifest.

Bug: 27458894
Change-Id: I1d81f9cd68a42d7346d2e42869542a365d2f024e
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 8892c24..babd271 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -324,6 +324,8 @@
             <meta-data android:name="android.telecom.IN_CALL_SERVICE_UI" android:value="true" />
             <meta-data android:name="android.telecom.IN_CALL_SERVICE_RINGING"
                 android:value="false"/>
+            <meta-data android:name="android.telecom.INCLUDE_EXTERNAL_CALLS"
+                       android:value="true"/>
             <intent-filter>
                 <action android:name="android.telecom.InCallService"/>
             </intent-filter>