Allow custom EqualityComparer on ViewModelBase.Set<T>() function

[SSchulze1989]

Feature description

The Set<T>() function does use the EqualityComparer<T>.Default default comparer which is great for most use-cases.
However if custom equality testing is required it means the function cannot be used.
With a simple overload it could be enabled to pass a custom comparer using the IEqualityComparer interface to the Set<T>() function without introducing any breaking changes.

Code sample

No response

[SSchulze1989]

I have opened a pr with the required changes:
#113