sweetspot explorer doesn't know to skip missing VTAs

[roysarel]

Describe the bug sweetspot explorer doesn't know to skip missing VTAs

To Reproduce Steps to reproduce the behavior: **1. run sweetspot explorer on a BIDS folder with some missing VTAs

2. you will get an error: Error using copy file**

Expected behavior Make it optional to run sweetspot explorer even in the case of some missing VTAs in the BIDS folder...

Screenshots

Environment: **- OS: macOS

• MATLAB version: R2023a
• Lead-DBS version: v3.0
• Lead-DBS setup: cloned github repository, developer branch**

Thanks!