Move wordcloud template settings into metadata, and remove contents of…

Move wordcloud template settings into metadata, and remove contents of definition (since no fields edited by studio authors have scope.settings)

common/lib/xmodule/xmodule/templates/word_cloud/default.yaml

@@ -2,6 +2,8 @@
 metadata:
     display_name: Word cloud
     version: 1
-data: |
-  <word_cloud num_inputs="5" num_top_words="250" display_student_percents="True" />
+    num_inputs: 5
+    num_top_words: 250
+    display_student_percents: True
+data: {}
 children: []