incorrect `collect` override

[nsajko]

It's not correct to "return only stored values".

NDimensionalSparseArrays.jl/src/ndsparsearray.jl

Lines 480 to 487 in 6fde3dc

	# Override collect to return only stored values
	"""
	collect(A::NDSparseArray)
	Collect only the stored values in the sparse array.
	To get a dense representation, use `to_dense(A)`.
	"""
	Base.collect(A::NDSparseArray) = collect(stored_values(A))