..F....... [ZBX-7545] fixed item mass update form being rendered with a delay when updating template items

Before the fix:
- Because of an incorrect API call, the mass update form for template items could be rendered with a delay on large installations with debug mode enabled. Submitting a form that hasn't been completely displayed, may had caused configuration data loss.

After the fix:
- The API call has been fixed and the form is rendered without any delays.