Return Transaction Id

[codeismail-waver]

Transaction id is nil in the payload returned to sdk integrators. This pr includes transaction id if it exists.

Before

  FlutterwaveDataResponse(
       txRef: txRef, 
       flwRef: flwRef, 
       deviceFingerprint: nil, 
       amount: amount, 
       chargedAmount: chargedAmount, 
       appFee: appFee,
       merchantFee: merchantFee, 
       processorResponse: processorResponse, 
       authModel: nil, 
       currency: currency, 
       ip: ip, 
       narration: narration, 
       status: status, 
       authURL:nil, 
       paymentType: nil, 
       fraudStatus: nil, 
       chargeType: nil, 
       createdAt: nil, 
       plan: nil, 
       id: nil, 
       accountID: nil, 
       customer: customer, card: nil)

After

  FlutterwaveDataResponse(
       txRef: txRef, 
       flwRef: flwRef, 
       deviceFingerprint: nil, 
       amount: amount, 
       chargedAmount: chargedAmount, 
       appFee: appFee,
       merchantFee: merchantFee, 
       processorResponse: processorResponse, 
       authModel: nil, 
       currency: currency, 
       ip: ip, 
       narration: narration, 
       status: status, 
       authURL:nil, 
       paymentType: nil, 
       fraudStatus: nil, 
       chargeType: nil, 
       createdAt: nil, 
       plan: nil, 
       id: id, //nullable id (returns id if it exist) 
       accountID: nil, 
       customer: customer, card: nil)

[kpoose]

Looks good to me