add description for browser perm to pass app validation

manifest.webapp

@@ -23,7 +23,9 @@
     "mobilenetwork": {
       "description": "Required to verify your phone number"
     },
-    "browser": {},
+    "browser": {
+      "description": "Required to improve performance"
+    },
     "audio-capture": {
        "description": "Required to capture audio via getUserMedia"
     },