[Large Screen] Launch MobileNetworkActivity as a fragment for split mode

Receive intent in MobileNetworkActivity and launch a activity which extend SettingsActivity

Test: atest
Bug: 197609014
Bug: 209606859
Change-Id: Ic07b18b3ea11744f240b25a0986474df763a199b
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index c4c682f..c49ee73 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -240,6 +240,7 @@
         <activity android:name=".network.telephony.MobileNetworkActivity"
                   android:label="@string/network_settings_title"
                   android:exported="true"
+                  android:taskAffinity="com.android.settings.root"
                   android:launchMode="singleTask"
                   android:configChanges="orientation|screenSize|keyboardHidden">
             <!-- Note: Since the framework does not support the multiple requests of network scan
@@ -257,6 +258,14 @@
             </intent-filter>
         </activity>
 
+        <activity
+            android:name=".Settings$SubscriptionSettingsActivity"
+            android:label="@string/network_settings_title"
+            android:exported="false">
+            <meta-data android:name="com.android.settings.FRAGMENT_CLASS"
+                       android:value="com.android.settings.network.telephony.MobileNetworkSettings"/>
+        </activity>
+
         <activity android:name=".Settings$MobileNetworkListActivity"
                   android:exported="true"
                   android:label="@string/network_settings_title">