Merge pull request #3845 from edx/zoldak/brittle-html-editor-tests

Wait for ajax to complete when editing components in Studio acceptance tests

cms/djangoapps/contentstore/features/component_settings_editor_helpers.py

@@ -122,6 +122,7 @@ def ensure_settings_visible():
 def edit_component():
     world.wait_for(lambda _driver: world.css_visible('a.edit-button'))
     world.css_click('a.edit-button')
+    world.wait_for_ajax_complete()
 
 
 @world.absorb