[BUG] rooms.info returns HTTP 500 for nonexistent rooms #42540

Description:

The rooms.info REST API endpoint throws an internal server error when the requested room does not exist.

When findRoomByIdOrName() returns null, the endpoint currently passes that value to isPublicRoom() and isPrivateRoom(). These helpers access room.t, causing a null dereference.

Steps to reproduce:

1. Start a Rocket.Chat server.
2. Create or use a valid user account.
3. Authenticate and obtain a user ID and authentication token.
4. Send the following request with a nonexistent room ID:

GET /api/v1/rooms.info?roomId=000000000000000000000000
X-User-Id: <user-id>
X-Auth-Token: <auth-token>