Fixing unmarshalling of numberOrString

New unmarshalling rules for fields which could be numeric or string
values were not properly typecasted upon being deserialized.

Cleaned up the api template file and moved custom unmarshalling type
logic into go code out of the template.

unifi/channel_plan.generated.go

@@ -133,6 +133,9 @@ func (dst *ChannelPlanRadioTable) UnmarshalJSON(b []byte) error {
 	if err != nil {
 		return fmt.Errorf("unable to unmarshal alias: %w", err)
 	}
+	dst.BackupChannel = string(aux.BackupChannel)
+	dst.Channel = string(aux.Channel)
+	dst.TxPower = string(aux.TxPower)
 	dst.Width = int(aux.Width)
 
 	return nil

unifi/device.generated.go

@@ -315,9 +315,12 @@ func (dst *DeviceRadioTable) UnmarshalJSON(b []byte) error {
 	}
 	dst.AntennaGain = int(aux.AntennaGain)
 	dst.AntennaID = int(aux.AntennaID)
+	dst.BackupChannel = string(aux.BackupChannel)
+	dst.Channel = string(aux.Channel)
 	dst.Maxsta = int(aux.Maxsta)
 	dst.MinRssi = int(aux.MinRssi)
 	dst.SensLevel = int(aux.SensLevel)
+	dst.TxPower = string(aux.TxPower)
 
 	return nil
 }