[EC-307] Fresh desk custom fields integration (#2114)

* Using correct ILogger on FreshdeskController

* Submitting custom fields to Freshdesk

* Set up FreshdeskController to use IHttpClientFactory

* Added unit test for FreshdeskController

* Moved ControllerCustomizeAttribute and ControllerCustomization to Common

* Modified FreshdeskController to use FreshdeskWebhookModel; Edited unit tests to use AutoFixture

src/Billing/Models/FreshdeskWebhookModel.cs

@@ -0,0 +1,16 @@
+using System.Text.Json.Serialization;
+
+namespace Bit.Billing.Models
+{
+    public class FreshdeskWebhookModel
+    {
+        [JsonPropertyName("ticket_id")]
+        public string TicketId { get; set; }
+
+        [JsonPropertyName("ticket_contact_email")]
+        public string TicketContactEmail { get; set; }
+
+        [JsonPropertyName("ticket_tags")]
+        public string TicketTags { get; set; }
+    }
+}