Fix audio playback on API 28 devices.

AndroidManifest.xml

@@ -96,7 +96,8 @@
                  tools:replace="android:allowBackup"
                  android:allowBackup="false"
                  android:theme="@style/TextSecure.LightTheme"
-                 android:largeHeap="true">
+                 android:largeHeap="true"
+                 android:networkSecurityConfig="@xml/local_audio_server_config">
 
     <meta-data
             android:name="com.google.android.geo.API_KEY"

res/xml/local_audio_server_config.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8"?>
+<network-security-config>
+    <domain-config cleartextTrafficPermitted="true">
+        <domain includeSubdomains="true">127.0.0.1</domain>
+    </domain-config>
+</network-security-config>