Remove appId from sample app (#2387)

## Goal
Remove test appId from the sample app. It should be specified locally in the environment config.

Author: bidetofevil

examples/ExampleApp/app/src/main/embrace-config.json

@@ -1,4 +1,3 @@
 {
-  "app_id": "PFAWK",
   "ndk_enabled": true
 }