It is not possible to use the Machine learning wizard

**System Information (please complete the following information):**
- Model Builder Version (available in Manage Extensions dialog): v17.18.0
- Visual Studio Version: 18.7.3

**Describe the bug**
- On which step of the process did you run into an issue: Train (model)
- Clear description of the problem: in the machine learning wizard of the model, at the training stage, in the machine learning wizard of the model, at the training stage: Could not load file or assembly 'Microsoft.CodeAnalysis.CSharp, Version=4.9.0.0. If you look at the Microsoft version.CodeAnalysis.CSharp, then it is 5.6.0, there is 4.9.2 in the list of possible ones, but there is no 4.9.0

**Screenshots**
If applicable, add screenshots to help explain your problem.

Start at the Model Builder machine learning wizard's Train step and reproduce the assembly-load failure with Model Builder v17.18.0 and Visual Studio 18.7.3. Trace the Microsoft.CodeAnalysis.CSharp version being requested versus the installed versions; done means the wizard completes model training without this load error.

Written by the indexing model from the issue text.