Add payment method type duplication check for google_pay

[ShankarSinghC]

Currently there is no duplication check for google pay and we will create a new payment method entry for every google pay payment CIT with "setup_future_usage": "on_session". This is not the case in cards as locker handles the card duplication. Since we do not have a parameter handle duplication check for a google pay, we have to go with a approach of a customer can have only one saved google pay payment method.

In this approach we list all the saved payment method for a customer during every google pay CIT and check if any of them have the payment_method_type is google_pay if it is then we just return already saved payment_method_id.