.Net: Fixed JSON schema name in Structured Outputs for generic types

[dmytrostruk]

Motivation and Context

Resolves: #9416

When C# type is passed as a response format to OpenAI chat completion service, we use the type name as JSON schema name. When the type is generic, its name will contain characters that are not allowed in JSON schema name according to OpenAI API. This PR fixes the issue by replacing invalid characters with empty string.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

[asvishnyakov]

Wouldn't it better to use fully qualified type names, as they are truly unique, and because OpenAI doesn't support symbols, use for example hash of string?

[dmytrostruk]

Wouldn't it better to use fully qualified type names, as they are truly unique, and because OpenAI doesn't support symbols, use for example hash of string?

@asvishnyakov Thanks for your feedback! I don't see a requirement for this property to be unique in OpenAI docs or usage of hash in their examples. It would be also nice to be consistent with Python implementation, which uses just a name.