Annotations fail to export in DeepLabCut format

**Describe the bug**
Annotations will not export in DeepLabCut format.

**To Reproduce**
1. Load DeepLabCut dataset
2. Click Project, go to edit bodyparts
3. Upload bodypart YAML file
4. Annotate images
5. Export annotations (DeepLabCut format) -- nothing happens, annotations do not export

**Expected behavior**
An h5 file is automatically downloaded.

**Desktop (please complete the following information):**
- OS: Windows OS
- Browser: Chrome
- Version: 139.0.7258.139