Spaces - re-jigger application name for new Spaces application

Summary: got some errors in my sandbox when I updated. this fixes them and I think is the right naming convention.

Test Plan: /settings/panel/emailpreferences/ started working again!  /spaces/ also loaded  unit tests passed without errors

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T8377

Differential Revision: https://secure.phabricator.com/D13103

src/applications/spaces/application/PhabricatorSpacesApplication.php

@@ -1,6 +1,6 @@
 <?php
 
-final class PhabricatorApplicationSpaces extends PhabricatorApplication {
+final class PhabricatorSpacesApplication extends PhabricatorApplication {
 
   public function getBaseURI() {
     return '/spaces/';