fix(front): broken image in deployments history if user is deleted (#198)

## 📝 Description

renderedtext/tasks#7755

How it currently looks:

![Screenshot 2025-04-03 at 14 24
20](https://github.com/user-attachments/assets/a87cd3df-7aa5-47c9-a7df-0a104b68a780)

How it looks after the change:

![Screenshot 2025-04-03 at 14 38
57](https://github.com/user-attachments/assets/297dede0-2579-4f42-a43f-2244bc033275)

## ✅ Checklist
- [x] I have tested this change
- [ ] This change requires documentation update

Author: VeljkoMaksimovic

front/lib/front/models/deployment_details.ex

@@ -61,11 +61,11 @@ defmodule Front.Models.DeploymentDetails do
     end
 
     def preload_triggerer(deployment = %__MODULE__{}, nil) do
-      %__MODULE__{
-        deployment
-        | author_name: Application.get_env(:front, :default_user_name),
-          author_avatar_url: FrontWeb.SharedHelpers.assets_path()
-      }
+      author_name = Application.get_env(:front, :default_user_name)
+      first_letter = author_name |> String.first() |> String.downcase()
+      avatar_url = "#{FrontWeb.SharedHelpers.assets_path()}/images/org-#{first_letter}.svg"
+
+      %__MODULE__{deployment | author_name: author_name, author_avatar_url: avatar_url}
     end
   end