Feat: Adding "Mark all as unfavourite option" in the Favourites screen

[jaivsh]

Describe the feature

The favourites screen currently displays only the favourited classes in listview across it. There are no relevant options to unfavourite all classes at once, and the user would have to mark the classes independently as unfavourite for each of the class in order to unfavourite all classes. This can be made easier with the help of a "Mark all as unfavourite" feature in the favourites screen.

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[jaivsh]

@avinashkranjan please assign me this!