URL scheme must be "http" or "https" for CORS request.

**Describe the bug**
When attempting to make a GET request to the /api/users/ endpoint using curl, the request fails with the following message:

Failed to fetch.
Possible Reasons:

CORS
Network Failure
URL scheme must be "http" or "https" for CORS request.

**To Reproduce**
Steps to reproduce the behavior:
1. Deploy Label Studio behind a load balancer or proxy (e.g. ALB/Nginx).
2. Send a curl request like:
curl -X 'GET' \
'https://domain/api/users/' \
-H 'accept: application/json' \
-H 'X-CSRFTOKEN: [my_token_here]'
5. Observe the failed response: Failed to fetch.
6.
**Expected behavior**
The API should return a JSON response with the list of users (assuming authentication is valid), without CORS/network errors.

**Screenshots**


**Environment (please complete the following information):**
- OS: [Docker]
- Label Studio Version [1.15.0]
- Deployment: AWS ECS (EC2), behind ALB

**Additional context**
ECS task has the following environment variables set:

SECURE_SSL_REDIRECT=true

SECURE_PROXY_SSL_HEADER=HTTP_X_FORWARDED_PROTO,https

CSRF_TRUSTED_ORIGINS=https://my.domain

Issue may be related to Django not recognizing forwarded HTTPS headers from proxy.