Azure blob support for io_storages fails for government cloud

**Describe the bug**
endpoints and URLs for services in usgovcloud cloud of azure are different than those in the public cloud. Because the URLs are hardcoded in models.py for the public cloud, there is not way to use azure blob storage as backend storage.

**To Reproduce**
Steps to reproduce the behavior:
1. must run in gov cloud
2. once installed, attempt to configure backend source for images that are in gov cloud blob storage container
3. end point error, cannot connect, etc.

**Expected behavior**
The type type of cloud should be something that can be configured (default public, but allow override to either govcloud or china cloud). this config item should result in appropriate endpoints and URLs for blob storage backend.

**Screenshots**
N/A
**Environment (please complete the following information):**
- OS: Ubuntu 22.04
- Label Studio Version [e.g. 1.17]

**Additional context**
see label_studio/io_storages/azure_blob/models.py line [74](https://github.com/HumanSignal/label-studio/blob/develop/label_studio/io_storages/azure_blob/models.py#L74C32-L74C48) and [247](https://github.com/HumanSignal/label-studio/blob/develop/label_studio/io_storages/azure_blob/models.py#L247C52-L247C77)