Remove unused files and enhance error handling in serializers.py

- Deleted the outdated backend dependency file for drf-spectacular.
- Removed an unused image from the frontend assets.
- Improved error handling in TasksSerializer by catching ObjectDoesNotExist in addition to AttributeError.

backend/igny8_core/modules/writer/serializers.py

@@ -1,5 +1,6 @@
 from rest_framework import serializers
 from django.db import models
+from django.core.exceptions import ObjectDoesNotExist
 from .models import Tasks, Images, Content
 from igny8_core.business.planning.models import Clusters, ContentIdeas
 
@@ -85,7 +86,7 @@ class TasksSerializer(serializers.ModelSerializer):
     def _get_content_record(self, obj):
         try:
             return obj.content_record
-        except AttributeError:
+        except (AttributeError, ObjectDoesNotExist):
             return None
 
     def get_content_html(self, obj):