fix: trace server does not notify the client when the state system is…

[aaanh]

… empty and the analysis is completed, resulting in infinite polling on the client side.

What it does

Adds a condition check on whether or not the analysis is complete and return a sufficient response to the client.

How to test

• Run trace server (incubator) in debug mode with Eclipse IDE
• Run theia-trace-extension locally
• Load a valid UST trace without any entry or exit calls (i.e. empty)
• Open Flame Chart view
• Should show an infinite analysis running loader

Follow-ups

n/a

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the instructions in this template

[bhufmann]

Thanks for the fix.