Add scenario option to authorization server conformance test

[tnorimat]

Background

The current authorization server conformance test does not support --scenario option while MCP client and server conformance test support that.

Solution

The authorization server conformance test also support --scenario option in the same manner MCP client and server conformance test support.

[tnorimat]

@pcarleton Hello, if the issue makes sense, could you assign me to the issue? I cannot assign myself to the issue.