Untitled diagrams are not exportable

[esadakcam]

Describe the bug

When the title of the diagram is empty, export options don't work

To Reproduce

1. Create a new diagram
2. Delete the title
3. Try exporting

Expected behavior

A diagram without title either should be exportable or an error message is shown

Screenshots

Environment

Details

 - OS: MacOS 14.4.1
 - Browser Chrome
 - Version 2.4.0