Enhancement: Ability to provide in a custom scaffold altogether

[milindgoel15]

Is your feature request related to a problem? Please describe.
Hi again, so I am currently adding support for Windows in my existing app which is purely material design-based. But my Windows app will use fluent UI design language so when using the same introduction screen widget, having a material scaffold does work yea but since it is a material scaffold, it creates a tint in the background even after I try to apply a mica or acrylic background colour as a global background color.

So I was wondering if the package could offer the ability to provide a custom scaffold altogether such that I could use the scaffold page coming from the fluent UI package or say make use of the introduction screen and other properties like navigation without having to deal with background tint.

Describe the solution you'd like
a constructor could be the one approach.

Describe alternatives you've considered
A different introduction screen provides the raw features except for the scaffold widget tree. Tho this would not be possible ig

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

Package version or git hash

• Version of IntroductionScreen [e.g. 3.1.12]