Updated response code for cloud storage preview not found 204 -> 404 (#…

…6727)

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### Motivation and context
Resolved #6675 

### How has this been tested?
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### License

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project.
  Feel free to contact the maintainers if that's a concern.

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Response code for empty cloud storage preview 204 -> 404 (<https://github.com/opencv/cvat/pull/6727>)
 - Organization now opened immediately after it is created (<https://github.com/opencv/cvat/pull/6705>)
 
 ### Deprecated

cvat/apps/engine/views.py

@@ -27,7 +27,6 @@
 from django.db.models.query import Prefetch
 from django.http import HttpResponse, HttpResponseNotFound, HttpResponseBadRequest
 from django.utils import timezone
-from http import HTTPStatus
 
 from drf_spectacular.types import OpenApiTypes
 from drf_spectacular.utils import (
@@ -2587,7 +2586,7 @@ def preview(self, request, pk):
  if not db_storage.has_at_least_one_manifest:
  result = cache.get_cloud_preview_with_mime(db_storage)
  if not result:
- return HttpResponse(status=HTTPStatus.NO_CONTENT)
+ return HttpResponseNotFound('Cloud storage preview not found')
  return HttpResponse(result[0], result[1])
 
  preview, mime = cache.get_or_set_cloud_preview_with_mime(db_storage)