remove unused variables from android sample

Author: sbSteveK

samples/Android/app/src/main/java/software/amazon/awssdk/iotsamples/MainActivity.java

@@ -152,12 +152,8 @@ private void loadAssets(){
         resourceNames.add("endpoint.txt");
         resourceNames.add("privatekey.pem");
         resourceNames.add("certificate.pem");
-        resourceNames.add("cognitoIdentity.txt");
-        resourceNames.add("signingRegion.txt");
         resourceNames.add("keychainAlias.txt");
-        resourceNames.add("verbosity.txt");
         resourceNames.add("clientId.txt");
-        resourceNames.add("thingName.txt");
         resourceNames.add("topic.txt");
         resourceNames.add("message.txt");
         resourceNames.add("count.txt");