[BUG] Using Message Bus from a tool with no connections fails

[daryllabar]

Without having a service connection,

1. I triggered an opening of the EBGV2 from the VS Solution Accelerator.
2. It opened fine, asked if I wanted to connect, I said no.
3. Then I clicked a button that requires a connection, so the select a connection dialog showed
4. I selected a connection and let the EBGV2 task finish.
5. I then closed the EBGV2 tab.
6. Now on the VS Solution Accelerator tab once more, it shows no connection.
7. I repeated the same steps above and I get a null ref error here on line 730 in the NewForm.cs file:
   

Not sure if we need to clear the service, or maybe we need to check we have a connectionDetail record. or something else. It's not a big deal but I figured I'd report it.