[Auth] Pass through server error messages to the error object when available

[sam-gc]

Fixes #5386

In keeping with the new error format, the message is in error.customData.message instead of error.message.

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Latest commit: d44e170

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
@firebase/auth	Patch
@firebase/auth-compat	Patch
firebase	Patch

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Affected Products

No changes between base commit (bc3b405) and head commit (1bf8625).

Test Logs

• Base (bc3b405): https://github.com/firebase/firebase-js-sdk/actions/runs/1187786625
• Head (1bf8625): https://github.com/firebase/firebase-js-sdk/actions/runs/1188028941

[lisajian]

LGTM, do we need to update the example in https://cloud.google.com/identity-platform/docs/blocking-functions#blocking_registration_or_sign-in since the error is in customData? I think the only bit that needs to be updated is error.message.indexOf('Cloud Function') !== -1 should be error.customData.message.indexOf('Cloud Function') !== -1

[sam-gc]

In this case we shouldn't update the Cloud Identity Platform docs since the v9 SDK remains in beta for the Cloud Identity Platform features. We will need to update the compatibility layer to put the fields on the error instead of error.customData, but that's a larger PR that I'll do a bit later