Refactor envelope rejection logic in EnvelopeController

Clarified and streamlined the handling of rejected envelopes:
- Moved retrieval of rejecting receivers for clarity.
- Signed out users when any rejecting receivers are present.
- Improved determination of "external" users.
- Updated condition for showing the EnvelopeRejected view.
- Temporarily hardcoded ViewBag.IsExt with a TODO for future fix.
- Removed redundant code for better maintainability.

EnvelopeGenerator.Web/Controllers/EnvelopeController.cs

@@ -79,14 +79,16 @@ public class EnvelopeController : ViewControllerBase
                 return this.ViewEnvelopeNotFound();
 
             #region Rejected or Signed
-            //check rejection
-            if (er.Envelope.IsReadAndSign())
-            {
             var rejRcvrs = await _historyService.ReadRejectingReceivers(er.Envelope!.Id);
             if (rejRcvrs.Any())
             {
                 await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
-                    ViewBag.IsExt = !rejRcvrs.Contains(er.Receiver);    //external if the current user is not rejected
+                var isExt = !rejRcvrs.Where(rcv => rcv.Id == er.Receiver!.Id).Any();    //external if the current user is not rejected
+
+                if (er.Envelope.IsReadAndSign() || !isExt)
+                {
+                    //TODO: Normally assigned to the isExt variable. However, since the relevant keys are not defined in the resx files, it was assigned false. Fix this.
+                    ViewBag.IsExt = true;
                     return View("EnvelopeRejected", er);
                 }
             }
@@ -166,14 +168,17 @@ public class EnvelopeController : ViewControllerBase
             }
             var er_secret = er_secret_res.Data;
 
-            //check rejection if the envelope is read-and-sign
-            if (er_secret.Envelope.IsReadAndSign())
-            {
             var rejRcvrs = await _historyService.ReadRejectingReceivers(er_secret.Envelope!.Id);
             if (rejRcvrs.Any())
             {
                 await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
-                    ViewBag.IsExt = !rejRcvrs.Contains(er_secret.Receiver);    //external if the current user is not rejected
+                var isExt = !rejRcvrs.Where(rcv => rcv.Id == er_secret.Receiver!.Id).Any();    //external if the current user is not rejected
+
+                //check rejection if the envelope is read-and-sign or non-external (internal)
+                if (er_secret.Envelope.IsReadAndSign() || !isExt)
+                {
+                    //TODO: Normally assigned to the isExt variable. However, since the relevant keys are not defined in the resx files, it was assigned false. Fix this.
+                    ViewBag.IsExt = true;
                     return View("EnvelopeRejected", er_secret);
                 }
             }