Fixed code generation of primitive types (#354)

## Changes
<!-- Summary of your changes that are easy to understand -->
Use primitive types in response.

## Tests
<!-- 
How is this tested? Please see the checklist below and also describe any
other relevant tests
-->
SDK generation at current spec: `deco openapi generate-sdk py
--openapi-spec 09a7fa63d9ae243e5407941f200960ca14d48b07`
- [ ] `make test` run locally
- [ ] `make fmt` applied
- [ ] relevant integration tests applied

Author: tanmay-db

.codegen/service.py.tmpl

@@ -310,7 +310,7 @@ self._api.do('{{.Verb}}',
 {{define "method-return-type" -}}
   {{if and .Wait (and (not .IsCrudRead) (not (eq .SnakeName "get_run"))) }} -> Wait[{{.Wait.Poll.Response.PascalName}}]
   {{- else if .Response}} -> {{if .Response.ArrayValue -}}
-    Iterator[{{.Response.ArrayValue.PascalName}}]
+    Iterator[{{template "type" .Response.ArrayValue}}]
   {{- else if .Pagination -}}
     Iterator[{{.Pagination.Entity.PascalName}}]
   {{- else -}}