Less support when defining types like `stream<http:SseEvent, error?>` in the type field in the forms

[dulajdilshan]

Description

Steps to Reproduce

When selecting a type, it does not have support in defining a type like stream<http:SseEvent, error?>. No completion support is provided, the type needs to be manually typed

Version

Usability Test Pack 2026Q1

Environment Details (with versions)

No response