FedCM: An approved_clients entry in the accounts list is required for auto reauthentication to work

### MDN URL

https://developer.mozilla.org/en-US/docs/Web/API/FedCM_API/IDP_integration

### What specific section or headline is this issue about?

approved_clients

### What information was incorrect, unhelpful, or incomplete?

The documentation shows no description for what `approved_clients` is used for.

### What did you expect to see?

It should mention that the array of `approved_clients` will be checked when a client requests login. If the client id is found in the list, no disclosure text is displayed to the user.
It should also mention that for auto reauthentication to work, the client id of the RP should be in the array.

### Do you have any supporting links, references, or citations?

https://w3c-fedid.github.io/FedCM/#browser-connected-accounts-set states:
> When asked whether an [IdentityProviderAccount](https://w3c-fedid.github.io/FedCM/#dictdef-identityprovideraccount) account is eligible for auto reauthentication given an [IdentityProviderConfig](https://w3c-fedid.github.io/FedCM/#dictdef-identityproviderconfig) provider and a globalObject, run the following steps. This returns a boolean.
> 1. If account [contains](https://infra.spec.whatwg.org/#map-exists) [approved_clients](https://w3c-fedid.github.io/FedCM/#dom-identityprovideraccount-approved_clients) and account’s [approved_clients](https://w3c-fedid.github.io/FedCM/#dom-identityprovideraccount-approved_clients) does not [contain](https://infra.spec.whatwg.org/#list-contain) provider’s [clientId](https://w3c-fedid.github.io/FedCM/#dom-identityproviderconfig-clientid), return false.

### Do you have anything more you want to share?

_No response_

### MDN metadata

Page report details

* Folder: `en-us/web/api/fedcm_api/idp_integration`
* MDN URL: https://developer.mozilla.org/en-US/docs/Web/API/FedCM_API/IDP_integration
* GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/api/fedcm_api/idp_integration/index.md
* Last commit: https://github.com/mdn/content/commit/2b6f99e45534ce662f842d8b4d2f7845492e353c
* Document last modified: 2024-08-17T01:09:59.000Z