refactor: base64 decode overseer script contents (doubtfire-lms#547)

- Attempt to fix firewall issues

Author: b0ink

app/api/task_definitions_api.rb

@@ -915,7 +915,9 @@ class TaskDefinitionsApi < Grape::API
 
     script_path = td.task_assessment_script
 
-    File.write(script_path, params[:script_content])
+    decoded = Base64.urlsafe_decode64(params[:script_content])
+
+    File.write(script_path, decoded)
     status 200
   end