[FR] Support for defaultSupportedIdpConfigs

[IainAdams]

Is your feature request related to a problem? Please describe.
The REST/GRPC API provides the ability to manage defaultSupportedIdpConfigs, however, this doesn't seem available from the Admin SDK. Please could you add support for these types of IDPs.

Describe the solution you'd like
Similar to being able to manage SAML and OIDC providers, please add into the SDK methods for managing default supported idp configs.

Describe alternatives you've considered
Calling the REST/gRPC APIs separately but this involves having to handle all the API handling framework already being completed by the Admin SDK.

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[bojeil-google]

This is something we want to eventually support but will likely come later in the future.

[IainAdams]

It seems like such an easy thing to add in as basically so similar to the existing OIDC and SAML features. I'll try and do a PR although I am currently having issues building v8.10.0 with Node v12.13.0 and npm 6.12.0. I know you say it supports v8.x + but have you tried building against Node v12?

[hiranya911]

We have some tests that won't build/run on Node 12 (see #739). So you cannot currently develop on Node 12.

Also, we cannot accept any PRs for this functionality until the Firebase Auth team decides to officially support it in the SDK. According to the comment by @bojeil-google it appears they are still thinking about it. Therefore before you invest time into implementing any new code, I'd advise you to submit a feature request at https://firebase.google.com/support so that the Auth team can prioritize this accordingly.

[IchordeDionysos]

@lahirumaramba is there any news on the support for this feature?