Avoid activity restart by config changes while test

hostside/VpnTest assumes MyActivity launched at setup is not destroyed.
Test fails if the activity is restarted since mActivity in VpnTest
refers to the destroyed activity and mActivity.getResult can not return
result from vpn dialog.

Configuration changes specified in android:configChanges will not
restart activity but call Activity#onConfigurationChanged.

Test: atest com.android.cts.net.HostsideVpnTests#testSocketClosed
Bug: 277344807
Change-Id: Ia26e3c6495be63191bbfe6378c246ffb6d15be5a
diff --git a/tests/cts/hostside/app/AndroidManifest.xml b/tests/cts/hostside/app/AndroidManifest.xml
index 56d3cb5..ca3397b 100644
--- a/tests/cts/hostside/app/AndroidManifest.xml
+++ b/tests/cts/hostside/app/AndroidManifest.xml
@@ -34,7 +34,8 @@
 
     <application android:requestLegacyExternalStorage="true">
         <uses-library android:name="android.test.runner"/>
-        <activity android:name=".MyActivity"/>
+        <activity android:name=".MyActivity"
+                  android:configChanges="density|fontScale|keyboard|keyboardHidden|layoutDirection|locale|mcc|mnc|navigation|screenLayout|screenSize|smallestScreenSize|touchscreen|uiMode"/>
         <service android:name=".MyVpnService"
              android:permission="android.permission.BIND_VPN_SERVICE"
              android:exported="true">