Type of change

• Bug fix
• New feature development
• Tech debt (refactoring, code cleanup, dependency upgrades, etc)
• Build/deploy pipeline (DevOps)
• Other

Objective

Further changes required for bitwarden/web#1332.
As discussed here, we now set the SSO configuration defaults in the client-side form, instead of constructing an empty SsoConfigurationData class with defaults and sending it to the client. This PR removes the server-side defaults to avoid confusion about where they're set.

Code changes

• src/Api/Models/Response/OrganizationSsoResponseModel.cs - leave the Data property null instead of constructing an object with default values.
• src/Core/Models/Data/SsoConfigurationData.cs - convert all the Url building methods to static methods. This is required now that we may not have an SsoConfigurationData instance in some cases. They actually didn't use any instantiated class properties, so this is more accurate anyway.

Testing requirements

See main ticket

Before you submit

• I have checked for formatting errors (dotnet tool run dotnet-format --check) (required)
• If making database changes - I have also updated Entity Framework queries and/or migrations
• I have added unit tests where it makes sense to do so (encouraged but not required)
• This change requires a documentation update (notify the documentation team)
• This change has particular deployment requirements (notify the DevOps team)