Describe the bug:
When opening a version 2.30 diagram that contains a trust boundary box, in version 2.3.0 this

Expected behaviour:
when opening a legacy diagram that contains a trust boundary box, the correct label should be applied

Environment:

• Version: 2.4.0
• Platform: both Web App / Desktop App
• OS: all of MacOS / Windows / Linux
• Browser: all of e.g. chrome, firefox, safari

To Reproduce:

1. open the attached threat model in version 2.30, observe no label for the trust boundary box
2. open the model in version 2.4.0, observe label for the trust boundary box is 'Trust Boundary'
3. edit the label / name of the trust boundary box and observe it is now correctly changed to 'O/S File system'

Any additional context, screenshots, etc:
version 2.30 threat model with a trust boundary box :

trust-boundary-bug.json