Cleaning up fruits.dart

[Maheen-Ilyas]

The Fruit class is present in the main file. It should be placed in the models folder. The name of the navigate function should be changed to avoid confusion

[Shubham-Zone]

@VaibhavCodeClub please assing this task to me i am GSSOC'24 contributor

[Maheen-Ilyas]

I created the issue and it was assigned to someone else.