Multi Part Form Serialisation breaks for Swagger UI based requests

[shukpa]

While testing flow triggering with multipart/form-data Content Type with Swagger UI, an options parameter is added by default. This caused the serialisation to break as options parameter is a nested structured object, that requires to be treated as such.

[shukpa]

The options parameter is passed from Swagger UI as a JSON object. According to the OpenAPI spec, application/json Content Type is supported as a field within a multipart/form-data request. However, the jetty library provided MultiPartContentProvider does not have an appropriate method for adding application/json content. We will open a request so that jetty can support such methods. This is preventing us from introducing a test case for this flow.