Unable to re-open a tb7 file after using the Microsoft Threat Model (AzureArchitecture) template

[tony-mykhaylovsky-va]

Thank you for considering to respond

Describe the bug
Created a Threat Model Diagram, saved it, the next day, tried to re-open the file and received error:
System.FormatException: Input string was not in a correct format.

Can't open any other tb7 files either

To Reproduce
Steps to reproduce the behavior:

1. Go to Downloads folder
2. Click on .tb7 diagram file
3. Receive an error and can't preview the diagram

Expected behavior
The diagram we created yesterday

Screenshots

Desktop (please complete the following information):

• OS: Windows 11
• Browser N/A
• Version 7.3.31026.3

[wedge206]

fix #13