Removes teh DD mandate amount from the public model. Not currently being used and causes confusion. (#435)

Author: sipsorcery

src/NoFrixion.MoneyMoov/Models/Mandates/Mandate.cs

@@ -112,11 +112,14 @@ public class Mandate
     /// <summary>
     /// Currency of this mandate.
     /// </summary>
-    public CurrencyTypeEnum Currency { get; set; }
-    
+    public CurrencyTypeEnum Currency { get; set; }
+
     /// <summary>
-    /// Amount of this mandate.
+    /// This is an optional field that with mandates created via Account Information Services can be
+    /// used to do a balance check on the payer's account. We don't currenlty support the AIS workflow.
     /// </summary>
+    [System.Text.Json.Serialization.JsonIgnore]
+    [Newtonsoft.Json.JsonProperty]
     public decimal Amount { get; set; }
 
     /// <summary>

src/NoFrixion.MoneyMoov/Models/Mandates/MandateCreate.cs

@@ -124,10 +124,11 @@ public class MandateCreate
     public CurrencyTypeEnum Currency { get; set; }
 
     /// <summary>
-    /// Amount of the mandate.
+    /// This is an optional field that with mandates created via Account Information Services can be
+    /// used to do a balance check on the payer's account. We don't currenlty support the AIS workflow.
     /// </summary>
-    [Required(ErrorMessage = "Please, specify an amount.")]
-    [Range(0.00001, double.MaxValue, ErrorMessage = "Minimum value of 0.00001 is required for Amount")]
+    [System.Text.Json.Serialization.JsonIgnore]
+    [Newtonsoft.Json.JsonProperty]
     public decimal Amount { get; set; }
 
     /// <summary>