Enable structural equality checks for dynamic members of type IEnumerable

[kMutagene]

https://stackoverflow.com/questions/17101329/f-sequence-comparison

We might want to do structural equality check in Equals, as dynamic members having type seq<'A> will fail on comparison even when they have the same items. This might be the last improvement to enable structural equality checks for charts in Plotly.NET.

[kMutagene]

I think this is covered by our new hash code logic @HLWeil ?

[HLWeil]

Should be, but I don't see a test case for this. So maybe we could first add that before closing this issue.