bug: auth:export and auth:import silently discard MFA user data (mfaInfo)

[VishalRaut2106]

Description

When migrating users between Firebase projects or performing backups using the Firebase CLI commands firebase auth:export and firebase auth:import, Multi-Factor Authentication (MFA) enrollment configurations (mfaInfo) are silently discarded.

MFA runtime support was introduced to the Firebase Auth Emulator in PR #3173, but support was never extended to the CLI import/export tools, leaving two TODO comments in the codebase.

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Technical Details & Code Analysis

1. Exporter Limitations (src/accountExporter.ts)

In accountExporter.ts, the user objects returned from the Google Identity Toolkit REST API (downloadAccount endpoint) are filtered using a whitelist.

• EXPORTED_JSON_KEYS misses the mfaInfo key:

  const EXPORTED_JSON_KEYS = [
    "localId",
    "email",
    "emailVerified",
    "passwordHash",
    ... // mfaInfo is missing here
  ];