Use generic return type for runWithPermissions functions.

[acsbendi]

This can be useful to preserve the original function's return type. My use case:

interface InterfaceWithUnitMethod{
        fun unitMethod()
}
class MyFragment() : Fragment(), InterfaceWithUnitMethod{
       override fun unitMethod() = runWithPermissions(...){
                ...
       }
}

The override will only work if the return type matches the interface's, that is, Unit. Therefore, the previous Any? return type won't work in this scenario.