iauth-interface: include issuer field as defined in spec

[suhussai]

Describe the feature

The well-known openid config contains an issuer field. We should have something similar in the iauth-interface.

https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderMetadata

Use Case

When using the iauth-interface with a compliant library, we need to provide some value for the issuer. We can technically formulate that by editing existing fields, but it would be better to have a dedicated field for the issuer.

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

2.140.1

Environment details (OS name and version, etc.)

Mac OS