Remove xsrfScope and xsrfProtection authentication attributes

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=159121132

java/google/registry/request/Route.java

@@ -42,9 +42,4 @@ abstract class Route {
     }
     return false;
   }
-
-  boolean shouldXsrfProtect(Action.Method requestMethod) {
-    return action().xsrfProtection()
-        && (requestMethod != Action.Method.GET) && (requestMethod != Action.Method.HEAD);
-  }
 }