GraphQL: Improve session token error messages (#5753)

* GraphQL: Improve session token error message

Fixes the session token related error messages during GraphQL operations. If any authentication error were thrown, it was not correctly handled by the GraphQL express middleware, and ended responding the request with a JSON parsing error.

* Refactor handleError usage

* Use handleParseErrors middleware to handle invalid session token error

* fix: Status code 400 when session token is invalid

* fix: Undo handleParseErrors middleware change

src/GraphQL/parseGraphQLUtils.js

@@ -0,0 +1,14 @@
+import Parse from 'parse/node';
+import { ApolloError } from 'apollo-server-core';
+
+export function toGraphQLError(error) {
+  let code, message;
+  if (error instanceof Parse.Error) {
+    code = error.code;
+    message = error.message;
+  } else {
+    code = Parse.Error.INTERNAL_SERVER_ERROR;
+    message = 'Internal server error';
+  }
+  return new ApolloError(message, code);
+}