fix: Allow cross origin requests for Blockly assets. (#9342)

Author: gonfunko

appengine/app.yaml

@@ -70,6 +70,8 @@ handlers:
 # Blockly files.
 - url: /static
   static_dir: static
+  http_headers:
+    Access-Control-Allow-Origin: "*"
   secure: always
 
 # Storage API.