fix: remove namespace filtering from create_model

[andreitava-uip]

Context

Previously we were filtering the returned namespace and renaming the types. This was redundant, and if anything, the filtering and renaming actively hurt it and caused bugs in forward ref resolution when defs only referenced by other defs were involved.

Easiest way to reproduce problems is to set static args for nested fields. Because the static args flow converts the pydantic model back to json schema for parsing. This roundtrip converts previous inline objects to refs, with some refs not referenced by root.

{"Code":"AGENT_RUNTIME.UNEXPECTED_ERROR","Title":"Unexpected error: PydanticUserError","Detail":"An unexpected error occurred during agent execution, please try again later or contact your Administrator.\nError Details:\nSend_Message_to_Useris not fully defined; you should define__Dynamictype_3, then call Send_Message_to_User.model_rebuild().\n\nFor further information visit <https://errors.pydantic.dev/2.12/u/class-not-fully-defined>","Category":"Unknown","Status":null}

Fix

Simply remove the filtering logic and use the returned namespace as is.

Validation and testing

After the fix, the is not fully defined error disappears and tool static args works as intended.
Job attachment extraction logic has been validated and still works as expected (the job attachment type is correctly identified and resolved)