Is your feature request related to a problem? Please describe.
No, it's not a problem per se. I just think that the use of a logo makes the app appear more recognizable.

Describe the solution you'd like
Add a parameter and underlying code to Register-PnPAzureADApp to support setting the logo for the app that will be registered.
The parameter can reference a file path to an image file containing the logo

Describe alternatives you've considered
Manual configuration of the logo is possible, but comes with an additional stap opposed to a complete automation of creating and configuring the registration.

Additional context
Add any other context or screenshots about the feature request here.