Public client guidance out of date

> Please provide us with the following information:
> ---------------------------------------------------------------

### This issue is for a: (mark with an `x`)
```
- [ ] bug report -> please search issues before submitting
- [ ] feature request
- [X] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
Guidance in section 1 -> "Register the client app" -> step 6 is out of date with current Azure portal

### Any log messages given by the failure
> N/A

### Expected/desired behavior
> "Public client (mobile & desktop)" is no longer a platform option under Authentication tab in Azure portal. https://localhost is no longer a suggested redirect URI when selecting closest platform match ("Mobile and desktop applications"). Tutorial guidance in step 6 should be updated to match current UI.

### OS and Version?
> N/A

### Versions
> N/A

### Mention any other details that might be useful

> ---------------------------------------------------------------
> Thanks! We'll be in touch soon.