Update `gen-iterators.go` to handle edge cases

[Not-Dhananjay-Mishra]

While working on #3978
Generated Iter test fail because it does not handle some edge cases like []string
If there is a array of object it will work fine.

testJSON1 := strings.ReplaceAll(testJSON, "[]", "[{},{},{}]")    // Call 1 - return 3 items
testJSON2 := strings.ReplaceAll(testJSON, "[]", "[{},{},{},{}]") // Call 1 part 2 - return 4 items
testJSON3 := strings.ReplaceAll(testJSON, "[]", "[{},{}]")       // Call 2 - return 2 items

but if we have array of string or int then it will fail..

[Not-Dhananjay-Mishra]

@gmlewis If you want to work on this, feel free to open a PR 😃