Sort frames during project dumping (#6927)

When we export a task or project in CVAT format [our code
uses](https://github.com/opencv/cvat/blob/d497bb6a90dd3c9625c3c8e8f73278019e21983d/cvat/apps/dataset_manager/formats/cvat.py#L717)
the `group_by_frame` function. For tasks and for projects behaviour of
this function is different since for tasks [we perform sorting
frames](https://github.com/opencv/cvat/blob/d497bb6a90dd3c9625c3c8e8f73278019e21983d/cvat/apps/dataset_manager/bindings.py#L420-L421)
but for projects [we
don't](https://github.com/opencv/cvat/blob/d497bb6a90dd3c9625c3c8e8f73278019e21983d/cvat/apps/dataset_manager/bindings.py#L1152-L1154).
As a result, we can have a situation when our annotation file for the
project will have a list of images in unsorted form. So this PR adds
sorting frames during project export as well.

CHANGELOG.md

@@ -68,9 +68,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Downloading additional data from cloud storage if use_cache=true and job_file_mapping are specified
   (<https://github.com/opencv/cvat/pull/6879>)
 - Leaving an organization (<https://github.com/opencv/cvat/pull/6422>)
+- Order of images in annotation file when dumping project in CVAT format (<https://github.com/opencv/cvat/pull/6927>)
 - Validation on Cloud Storage form / error message on create task form (<https://github.com/opencv/cvat/pull/6890>)
 
-
 ## \[2.7.1\] - 2023-09-15
 
 ### Fixed

cvat/apps/dataset_manager/bindings.py

@@ -1149,7 +1149,7 @@ def get_frame(task_id: int, idx: int) -> ProjectData.Frame:
             return frames[(frame_info["subset"], abs_frame)]
 
         if include_empty:
-            for ident in self._frame_info:
+            for ident in sorted(self._frame_info):
                 if ident not in self._deleted_frames:
                     get_frame(*ident)