Fix missing EditEngineConfig on indirect pathway through conduit.query

Summary: Fixes T9772. We now need an EditEngineConfiguration to do interesting things with EditEngine, but this public API wasn't properly making sure we have one.

Test Plan: Called `conduit.query` from web console. Fatal prior to patch; success afterward.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T9772

Differential Revision: https://secure.phabricator.com/D14475

src/applications/transactions/editengine/PhabricatorEditEngine.php

@@ -961,6 +961,11 @@ abstract class PhabricatorEditEngine
   }
 
   public function getAllEditTypes() {
+    $config = $this->loadEditEngineConfiguration(null);
+    if (!$config) {
+      return array();
+    }
+
     $object = $this->newEditableObject();
     $fields = $this->buildEditFields($object);
     return $this->getAllEditTypesFromFields($fields);