Create balance monitor

monitor, _, _ := client.BalanceMonitor.Create(blnkgo.MonitorData{
	BalanceID: "bln_5ce86029-3c2e-4e2a-aae2-7fb931ca4c4f",
	Condition: blnkgo.MonitorCondition{
		Field: "credit_balance",
		Operator: blnkgo.OperatorGreaterThan,
		Value: 1000,
		Precision: 100,
	},
	CallBackURL: "https://api.example.com/balance-monitor",
	Description: "Low balance alert",
})

Field	Type	Description
BalanceID	string	Balance to monitor.
Condition	MonitorCondition	Threshold rule with Field, Operator, Value, and Precision.
Condition. Field	string	Balance field to watch (for example credit_balance, debit_balance, balance).
Condition. Operator	MonitorCondition Operators	Comparison operator: >, <, =, !=, >=, <=.
Condition. Value	int64	Threshold amount.
Condition. Precision	int64	Currency precision (for example 100 for cents).
CallBackURL	string	Webhook URL when the condition is met.
Description	string	Optional description for the monitor.

{
  "monitor_id": "mon_e0e77b0c-4985-472a-9bf5-76a48b0259b0",
  "balance_id": "bln_5ce86029-3c2e-4e2a-aae2-7fb931ca4c4f",
  "condition": {
    "field": "credit_balance",
    "operator": ">",
    "value": 1000,
    "precision": 100
  },
  "call_back_url": "https://api.example.com/balance-monitor",
  "description": "Low balance alert",
  "created_at": "2024-02-20T05:56:58.257315054Z"
}

Go response (*blnkgo.MonitorDataResp)

Field	Type	Description
MonitorID	string	Unique ID for the monitor.
BalanceID	string	Balance being monitored.
Condition	MonitorCondition	Threshold rule you passed in the request.
CallBackURL	string	Webhook URL for notifications.
Description	string	Description for the monitor.
CreatedAt	string	Date and time when the monitor was created.