fix(notification): enable web smtp test with saved password

Allow Web SMTP egress on TCP 587 and reuse the saved channel password only when connection settings match.

Ref: IT-1601

HrynCo.NotificationService.Web.IntegrationTests/RecordingAdminSmtpMediator.cs

@@ -0,0 +1,43 @@
+using System.Reflection;
+using HrynCo.NotificationService.DAL.Abstract.Providers;
+using HrynCo.NotificationService.Services.Core;
+using HrynCo.NotificationService.Services.EmailChannels.Get;
+using HrynCo.NotificationService.Services.EmailChannels.TestSmtp;
+using MediatR;
+using ServiceUnit = HrynCo.NotificationService.Services.Core.Unit;
+
+namespace HrynCo.NotificationService.Web.IntegrationTests;
+
+public class RecordingAdminSmtpMediator : DispatchProxy
+{
+    public EmailChannel? Channel { get; set; }
+    public TestSmtpCommand? SentCommand { get; private set; }
+    public int LookupCount { get; private set; }
+
+    protected override object Invoke(MethodInfo? targetMethod, object?[]? args)
+    {
+        if (targetMethod?.Name != nameof(IMediator.Send) || args?.Length is null or 0)
+            throw new NotSupportedException();
+
+        return args[0] switch
+        {
+            GetEmailChannelQuery => RecordLookup(),
+            TestSmtpCommand command => RecordSend(command),
+            _ => throw new NotSupportedException()
+        };
+    }
+
+    private Task<ServiceResult<EmailChannel>> RecordLookup()
+    {
+        LookupCount++;
+        return Task.FromResult(Channel is null
+            ? ServiceResult<EmailChannel>.Failure("Channel not found.")
+            : ServiceResult<EmailChannel>.Success(Channel));
+    }
+
+    private Task<ServiceResult<ServiceUnit>> RecordSend(TestSmtpCommand command)
+    {
+        SentCommand = command;
+        return Task.FromResult(ServiceResult<ServiceUnit>.Success(ServiceUnit.Value));
+    }
+}