Add message explaining why Standard view cannot be selected without commercial license

Currently, when not using a Commercial license, the Standard view is greyed out and cannot be selected on both onboarding Style selection and later selection in Preferences.

However, there is no message indicating that this is unavailable due to not having Commercial license. This may be disturbing to new users, especially as in the onboarding process, it's written "Recommended for new users" just below the Standard view description!

Stack Overflow question with image:

https://stackoverflow.com/questions/76925908/startup-window-smartgit-wont-let-me-select-to-standard-workflow-oriented