make oauth popup extensible to support firebase auth via plugin

https://securetoken.google.com/{MY_PROJECT}/.well-known/openid-configuration

returns this

{
    "issuer": "https://securetoken.google.com/{MY_PROJECT}",
    "jwks_uri": "https://www.googleapis.com/service_accounts/v1/jwk/securetoken@system.gserviceaccount.com",
    "response_types_supported": [
        "id_token"
    ],
    "subject_types_supported": [
        "public"
    ],
    "id_token_signing_alg_values_supported": [
        "RS256"
    ]

}

this is not a full openid configuration that would support the standard oauth flow

to enable custom firebase specific integration

i'd like to add my firebase specifi plugin to integrate with swagger

but to make the possible I need to hook with +- this logic rather than opening the window popup managed by swagger

firebase.initializeApp({...myconfig})

const firestore = firebase.firestore()
const auth = firebase.auth()

const provider = new firebase.auth.GoogleAuthProvider()
auth.signInWithPopup(provider).then(result =>
   result.token -> pass this to swagger
})

The issue names no files, tests, or specific entry points. Start by tracing Swagger UI's OAuth popup logic and its plugin extension points; done means a custom Firebase authentication plugin can control the popup flow and pass its token back to Swagger UI.