fix: Bug when adding spaces to containers names in course outline

- Fixes the bug introduced in #2732
- Removes the unnecessary `preventDefault`

Author: ChrisChV

src/course-outline/card-header/CardHeader.tsx

@@ -181,6 +181,12 @@ const CardHeader = ({
               onKeyDown={(e) => {
                 if (e.key === 'Enter') {
                   onEditSubmit(titleValue);
+                } else if (e.key === ' ') {
+                  // Avoid passing propagation to the `SortableItem` in the card,
+                  // which executes a `preventDefault`. If propagation is not prevented,
+                  // spaces cannot be added to names.
+                  /* istanbul ignore next */
+                  e.stopPropagation();
                 }
               }}
               disabled={isSaving}