[BUG] [Go] There is a problem with the parsing of 'anyof' fields in the yaml file

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

openapi-generator version 7.0.0-20220526.055920-1

OpenAPI declaration file content or url

Generation Details

Steps to reproduce

1. git clone https://forge.3gpp.org/rep/all/5G_APIs.git

2. Removed multipart/related part (line 196-213 and line 221-238.

3. run command: java -jar openapi-generator-cli-7.0.0-20220526.055920-1.jar generate -g go-echo-server -i 5g/5G_APIs/TS29532_Nmbsmf_MBSSession.yaml(https://forge.3gpp.org/rep/all/5G_APIs/-/blob/master/TS29532_Nmbsmf_MBSSession.yaml) -o ./out/echo-server-session

4. will generator model_context_status_event_type.go and model_context_status_event_type_any_of.go and model_context_status_event.go

5. My question is that : ContextStatusEventType is empty struct. why not use ContextStatusEventTypeAnyof in model_context_status_event.go?

Related issues/PRs

Suggest a fix

Reproduce the report with 5g/5G_APIs/TS29532_Nmbsmf_MBSSession.yaml using the listed openapi-generator-cli command. Inspect the generated model_context_status_event_type.go, model_context_status_event_type_any_of.go, and model_context_status_event.go files, then compare the generated ContextStatusEventType representation with the any-of model. Done means the generator produces the expected non-empty model relationship and a regression test covers this specification.