ArrayInterface 4 broke `OptionallyStaticUnitRange` iteration

[chriselrod]

julia> using ArrayInterface, Static

julia> for k ∈ static(1):static(5); @show k; end
k = 1
k = 2
k = 3
k = 4
k = 5
ERROR: BoundsError: attempt to access Missing at index [1]
Stacktrace:
 [1] top-level scope
   @ ./REPL[6]:1

julia> for k ∈ static(1):static(2):static(5); @show k; end
k = 1
k = 3
k = 5

iterate should return nothing and not missing.