Apply suggestion from @cquirosj

Author: cquirosj

src/ServiceControl/MessageFailures/Api/EditFailedMessagesController.cs

@@ -41,9 +41,8 @@ public async Task<ActionResult<EditRetryResponse>> Edit(string failedMessageId,
             if (editId != null)
             {
                 logger.LogWarning("Cannot edit message {FailedMessageId} because it has already been edited", failedMessageId);
-                // We return HTTP 200 even though the edit is being ignored. This is to keep the compatibility with older versions of ServicePulse.
-                // Newer ServicePulse versions (starting with x.x) will handle the response's payload accordingly.
-                return Ok(new EditRetryResponse { EditIgnored = true });
+                // We return HTTP 200 even though the edit is being ignored. This is to keep the compatibility with older versions of ServicePulse that don't handle the payload.
+                return Ok(new { EditIgnored = true });
             }
 
             var failedMessage = await store.ErrorBy(failedMessageId);