cast internal Auth to public Auth to make TS happy

Author: Feiyang1

packages-exp/auth-compat-exp/src/user.ts

@@ -47,7 +47,7 @@ export class User extends impl.UserImpl implements compat.User {
     credential: compat.AuthCredential
   ): Promise<compat.UserCredential> {
     return convertCredential(
-      this.auth,
+      (this.auth as unknown) as externs.Auth,
       impl.linkWithCredential(this, credential as externs.AuthCredential)
     );
   }
@@ -56,15 +56,15 @@ export class User extends impl.UserImpl implements compat.User {
     applicationVerifier: compat.ApplicationVerifier
   ): Promise<compat.ConfirmationResult> {
     return convertConfirmationResult(
-      this.auth,
+      (this.auth as unknown) as externs.Auth,
       impl.linkWithPhoneNumber(this, phoneNumber, applicationVerifier)
     );
   }
   async linkWithPopup(
     provider: compat.AuthProvider
   ): Promise<compat.UserCredential> {
     return convertCredential(
-      this.auth,
+      (this.auth as unknown) as externs.Auth,
       impl.linkWithPopup(
         this,
         provider as externs.AuthProvider,
@@ -88,7 +88,7 @@ export class User extends impl.UserImpl implements compat.User {
     credential: compat.AuthCredential
   ): Promise<compat.UserCredential> {
     return convertCredential(
-      this.auth,
+      (this.auth as unknown) as externs.Auth,
       impl.reauthenticateWithCredential(
         this,
         credential as externs.AuthCredential
@@ -100,15 +100,15 @@ export class User extends impl.UserImpl implements compat.User {
     applicationVerifier: compat.ApplicationVerifier
   ): Promise<compat.ConfirmationResult> {
     return convertConfirmationResult(
-      this.auth,
+      (this.auth as unknown) as externs.Auth,
       impl.reauthenticateWithPhoneNumber(this, phoneNumber, applicationVerifier)
     );
   }
   reauthenticateWithPopup(
     provider: compat.AuthProvider
   ): Promise<compat.UserCredential> {
     return convertCredential(
-      this.auth,
+      (this.auth as unknown) as externs.Auth,
       impl.reauthenticateWithPopup(
         this,
         provider as externs.AuthProvider,