Use metadata._copy instead of manually setting metadata

Author: mdedys

packages/auth/src/core/user/user_impl.ts

@@ -140,13 +140,15 @@ export class UserImpl implements UserInternal {
   }
 
   _clone(auth: AuthInternal): UserInternal {
-    return new UserImpl({
+    const newUser = new UserImpl({
       ...this,
-      createdAt: this.metadata.creationTime,
-      lastLoginAt: this.metadata.lastSignInTime,
       auth,
       stsTokenManager: this.stsTokenManager._clone()
-    });
+    })
+
+    newUser.metadata._copy(this.metadata)
+
+    return newUser;
   }
 
   _onReload(callback: NextFn<APIUserInfo>): void {