[BUG] Cubeviz: model fitting over the cube fails with spectral subset

[rosteen]

Describe the bug
If you select a spectral subset in the dropdown in Model Fitting before fitting over the cube, the result cube will come back with all 0 values.

To Reproduce
Steps to reproduce the behavior:

1. Select a subset in the spectrum viewer
2. Open model fitting, select the spectral subset, create a linear component model
3. Click "Apply to Cube"
4. Retrieve the fitted cube in the notebook, see that it's all 0.

Expected behavior
The fit will be done on the selected spectral region for every spaxel.

[pllim]

Is there a JIRA ticket for this? I cannot find it.