x/mobile: Array return type in exported functions is much recommended at earliest.

[ioArchman]

It would benefit if Array return type in exported functions is supported at the earliest. Looking forward.

[hyangah]

#13445 discusses support of slices of struct.
I think once we have a solution for it, we will have a story for general slice/array type support as well.
Let's move to #13445 for discussion and updates for now.