remove error when calling fieldtype on a Module

[KristofferC]

This was added in 8f08a1f to fix #13021 but it doesn't seem to be needed anymore.

Fixes #33347.

[JeffBezanson]

Since Module doesn't have usable fields (via getfield etc.) I suspect fieldtypes and fieldnames should return ().

[vtjnash]

That fact seems a bit muddy, since it does have usable fields via getfield, but we call the listing of them propertynames (or names) instead of fieldnames:

julia> getfield(Main, :Main)
Main

julia> propertynames(Main)
5-element Array{Symbol,1}:
...

[vtjnash]

Also, FWIW, we have now:

julia> fieldnames(Module)
(:name, :parent)

julia> fieldcount(Module)
2

So this PR would currently give also give the corresponding type of that pair (Symbol, Module) too

[JeffBezanson]

I guess fieldtypes isn't the most harmful of that lot, but I think they're all pretty misleading.