[Agent] Add API to add attachment to task message (#3327)

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#### Summary <!-- Provide a general summary of your changes -->
Add agent message API to add attachment to task message.

#### Work Item(s) <!-- Add the issue number here after the #. The issue
needs to be open and approved. Submitting PRs with no linked issues or
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Fixes
[AB#547967](https://dynamicssmb2.visualstudio.com/1fcb79e7-ab07-432a-a3c6-6cf5a88ba4a5/_workitems/edit/547967)

Author: darjoo

src/System Application/App/Agent/Interaction/AgentMessage.Codeunit.al

@@ -61,6 +61,20 @@ codeunit 4307 "Agent Message"
         AgentMessageImpl.SetStatusToSent(AgentTaskMessage);
     end;
 
+    /// <summary>
+    /// Add an attachment to the task message.
+    /// </summary>
+    /// <param name="FileName">The name of the file to be attached.</param>
+    /// <param name="FileMIMEType">The MIME type of the file to be attached.</param>
+    /// <param name="Attachment">The attachment stream.</param>
+    [Scope('OnPrem')]
+    procedure AddAttachment(var AgentTaskMessage: Record "Agent Task Message"; FileName: Text[250]; FileMIMEType: Text[100]; Attachment: InStream)
+    var
+        AgentMessageImpl: Codeunit "Agent Message Impl.";
+    begin
+        AgentMessageImpl.AddAttachment(AgentTaskMessage, FileName, FileMIMEType, Attachment);
+    end;
+
     /// <summary>
     /// Downloads the attachments for a specific message.
     /// </summary>

src/System Application/App/Agent/Interaction/AgentMessageImpl.Codeunit.al

@@ -47,6 +47,28 @@ codeunit 4308 "Agent Message Impl."
         UpdateAgentTaskMessageStatus(AgentTaskMessage, AgentTaskMessage.Status::Sent);
     end;
 
+    procedure AddAttachment(var AgentTaskMessage: Record "Agent Task Message"; FileName: Text[250]; FileMIMEType: Text[100]; InStream: InStream)
+    var
+        AgentTaskFile: Record "Agent Task File";
+        AgentTaskMessageAttachment: Record "Agent Task Message Attachment";
+        AgentTaskImpl: Codeunit "Agent Task Impl.";
+        OutStream: OutStream;
+    begin
+        // Add attachment to task file
+        AgentTaskFile."Task ID" := AgentTaskMessage."Task ID";
+        AgentTaskFile."File Name" := FileName;
+        AgentTaskFile."File MIME Type" := FileMIMEType;
+        AgentTaskFile.Content.CreateOutStream(OutStream, AgentTaskImpl.GetDefaultEncoding());
+        CopyStream(OutStream, InStream);
+        AgentTaskFile.Insert();
+
+        // Link task file to task message
+        AgentTaskMessageAttachment."Task ID" := AgentTaskMessage."Task ID";
+        AgentTaskMessageAttachment."Message ID" := AgentTaskMessage.ID;
+        AgentTaskMessageAttachment."File ID" := AgentTaskFile.ID;
+        AgentTaskMessageAttachment.Insert();
+    end;
+
     procedure DownloadAttachments(var AgentTaskMessage: Record "Agent Task Message")
     var
         AgentTaskFile: Record "Agent Task File";

src/System Application/App/Agent/Interaction/AgentTaskImpl.Codeunit.al

@@ -5,8 +5,8 @@
 
 namespace System.Agents;
 
-using System.Integration;
 using System.Environment;
+using System.Integration;
 
 codeunit 4300 "Agent Task Impl."
 {