Deep links screen shows "you selected a non Flutter project" when I have selected a flutter project

[kenzieschmoll]

Repro steps:

1. Open the devtools/ project
2. Open the Deep links screen from the IDE. A list of app roots should populate.
3. Select the app root ending in devtools_app/ (a flutter project)
4. Observe the error about selecting a non-flutter project

CC @chunhtai @hannah-hyj

[mikecasey12]

I'm also getting this issue in the devtools when I navigate to the deeplinks tab and the project is definitely a flutter project. Is there a fix for this?