[Task] Create an error message to prevent users from connecting multiple Ledger devices

[vivek-consensys]

When a user connects/adds a Ledger device account to MM Extension, we should prevent the user from connecting/adding another Ledger device into MM Extension without removing the previous connected device.

Currently, the user is able to add multiple Ledger devices on MM Extension, which is not part of the expected feature. The new Ledger SDK will prevent multiple ledger accounts to be added in the future.

Error to be added:-