fix(numbas): allow '.' in username param for SCORM route

Rails/Grape interprets '.' in a path segment as a format separator,
which broke lookups for usernames containing dots (e.g. "user.name").
Add a route requirement so :username matches any non-slash characters.

Author: Coskun Kilinc

app/api/scorm_api.rb

@@ -52,7 +52,9 @@ def stream_file_from_zip(zip_path, file_path)
   params do
     requires :task_def_id, type: Integer, desc: 'Task Definition ID to get SCORM test data for'
   end
-  get '/scorm/:task_def_id/:username/:auth_token/*file_path' do
+
+  # NOTE: allow '.' in username; without this Rails/Grape treats '.' as format.
+  get '/scorm/:task_def_id/:username/:auth_token/*file_path', requirements: { username: /[^\/]+/ }  do
     task_def = TaskDefinition.find(params[:task_def_id])
 
     unless authorise? current_user, task_def.unit, :get_unit