.Net: Bug: OpenApiDocumentParser fail when X-API-version is provide in the content key

[mickaelropars]

Describe the bug
in open OpenApiDocumentParser there is a bug whille retreiving the media type, from the response schema when the content has multiple attribute (in my case the x-api-version was also described)

To Reproduce
In the OpenApi schema we can have multiple type of information describing the content . In my case the description of the schema was "text/plain; x-api-version=2.0"

Expected behavior
OpenApiDocumentParser shall be able to retreive the mediatype from a complex content description

Platform

• OS: Windows
• IDE: Visual Studio
• Language: C#
• Source: Latest des

Additional context
Impact on the following methods of OpenApiDocumentParser

• CreateRestApiOperationPayload
• CreateRestApiOperationExpectedResponses

the line cause this error (in both methods)
var mediaType = s_supportedMediaTypes.FirstOrDefault(response.Value.Content.ContainsKey);

we should split and trim the splitted value to retrieve the mediatype