Handle error where file retrieval from ChRIS is undefined

[rahmatkhah]

Describe the bug
This occurs when no models are loaded in, meaning the jobs should not be completed (which should result in a failed analysis instead of the program crashing).

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Docker (please complete the following information):

• Docker version: [e.g. 20.10.10, build b485636]
• docker-compose version: [e.g. 1.29.2, build 5becea4c]

Additional context
@mslwang:

think the situation I brought up just isn't handled because we expect to have to have the plugins installed (but not necessarily registered). With minichris, the only way to have them referenced is when you register it with the links. So, I tried it with full chris instead, but without registering the plugins. Which shows a failed analysis, but opening the modal is undefined/leads to the same error.