Add xml config to allow cleartext traffic on some domains.

Cronet automatically prevents cleartext(http) traffic but we
need to allowlist the hosts used for testing.

Test: atest NetHttpCoverageTests
Bug: 267353182
Change-Id: Ie4ee41fac40ce80d0d76ec2e388c248d7366d334
diff --git a/Cronet/tests/mts/AndroidManifest.xml b/Cronet/tests/mts/AndroidManifest.xml
index 62c2060..f597134 100644
--- a/Cronet/tests/mts/AndroidManifest.xml
+++ b/Cronet/tests/mts/AndroidManifest.xml
@@ -21,7 +21,7 @@
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
     <uses-permission android:name="android.permission.INTERNET"/>
 
-    <application>
+    <application android:networkSecurityConfig="@xml/network_security_config">
         <uses-library android:name="android.test.runner" />
     </application>
     <instrumentation android:name="androidx.test.runner.AndroidJUnitRunner"