[csharp] Add scope for oauth2

[mjansrud]

[csharp] Add scope for oauth2 based on issue #17047.

When using the OAuth client credentials flow, the Configuration object allows me to specify the OAuthTokenUrl, OAuthClientId, and OAuthClientSecret, but there seems to be no way to specify any scope. Problem I'm facing is that I need to specify a scope to retrieve a token, so currently the request made in the OAuthAuthenticator.cs (GetToken() method) class returns a 400 response.

Microsoft identity platform documentation:
https://learn.microsoft.com/en-us/entra/identity-platform/v2-oauth2-client-creds-grant-flow

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@iBicha

[wing328]

thanks for the PR. can you please review the test failures when you've time?

[mjansrud]

I added LangVersion 8 to enable nullable strings in the netstandard2.0 sample projects to fix the tests. Im not sure if this is a ok solution, or if we want to solve the issue in another way. What do you think @wing328 ?

[wing328]

I added LangVersion 8 to enable nullable strings

can it be avoided if possible?

[mjansrud]

I think i found a decent solution by only setting the string as nullable on supported frameworks with templating rules. It seems like the variable can be set as a regular string in netstandard2.0, but still be defined as null. See the image screenshot attached. Can you run the rest of the tests? :)

[wing328]

looks like some samples are not yet up-to-date: https://github.com/OpenAPITools/openapi-generator/actions/runs/9970910212/job/27553889552?pr=19175

can you please regenerate the samples when you've time?

[mjansrud]

Ive updated the samples @wing328

[mjansrud]

Ive changed to {{nrt?}} as requested @devhl-labs. Does it look ok? And can one of you please generate the samples for me? That would be much appreciated @wing328 @devhl-labs. Upon test generation i get a deviation from main, and have to change the code manually, which is a real pain.

[mjansrud]

@wing328 can you run the last tests and take a final look?

[wing328]

https://github.com/OpenAPITools/openapi-generator/actions/runs/10005218697/job/27738318490?pr=19175

can you please update the samples?

[mjansrud]

Hi Wing. Did you see comment #19175 (comment)?

[wing328]

filed #19234 with updated samples. let's see how that goes

[wing328]

@mjansrud thanks for the PR, which has been merged via #19234 with updated samples (all tests passed)