[WEB-621] chore: 404 page not found (#3859)

* chore: custom 404 error

* chore: moved from middleware to view

apiserver/plane/app/views/__init__.py

@@ -187,4 +187,6 @@ from .webhook import (
 from .dashboard import (
     DashboardEndpoint,
     WidgetsEndpoint
-)
+)
+
+from .error_404 import custom_404_view

apiserver/plane/app/views/error_404.py

@@ -0,0 +1,5 @@
+# views.py
+from django.http import JsonResponse
+
+def custom_404_view(request, exception=None):
+    return JsonResponse({"error": "Page not found."}, status=404)

apiserver/plane/urls.py

@@ -7,6 +7,7 @@ from django.views.generic import TemplateView
 
 from django.conf import settings
 
+handler404 = "plane.app.views.error_404.custom_404_view"
 
 urlpatterns = [
     path("", TemplateView.as_view(template_name="index.html")),