Getting null response while using api to create prediction

Label-studio: 1.7.3
Label-studio-ml: 1.0.8rc3

API call from postman with response:

# Tried and failed:
- Turning webhook on & off
- Trying from CLI using curl

# Label Studio Logs
```
[2023-05-17 12:21:49,922] [django.server::log_message::161] [INFO] "GET /api/projects/18 HTTP/1.1" 200 3512
[2023-05-17 12:21:50,217] [django.server::log_message::161] [INFO] "POST /api/projects/18/sample-task HTTP/1.1" 200 54
[2023-05-17 12:21:50,217] [django.server::log_message::161] [INFO] "POST /api/projects/18/sample-task HTTP/1.1" 200 54
[2023-05-17 12:21:51,517] [django.server::log_message::161] [INFO] "GET /api/projects/18/summary HTTP/1.1" 200 387
[2023-05-17 12:21:51,517] [django.server::log_message::161] [INFO] "GET /api/projects/18/summary HTTP/1.1" 200 387
[2023-05-17 12:21:51,562] [django.server::log_message::161] [INFO] "GET /api/projects/18 HTTP/1.1" 200 3512
[2023-05-17 12:21:51,562] [django.server::log_message::161] [INFO] "GET /api/projects/18 HTTP/1.1" 200 3512
[2023-05-17 12:22:50,775] [django.server::log_message::161] [INFO] "POST /api/predictions/ HTTP/1.1" 201 234
[2023-05-17 12:22:50,775] [django.server::log_message::161] [INFO] "POST /api/predictions/ HTTP/1.1" 201 234
[2023-05-17 12:24:17,274] [django.server::log_message::161] [INFO] "POST /api/predictions/ HTTP/1.1" 201 234
[2023-05-17 12:24:17,274] [django.server::log_message::161] [INFO] "POST /api/predictions/ HTTP/1.1" 201 234
[2023-05-17 12:24:55,259] [django.server::log_message::161] [INFO] "POST /api/predictions/ HTTP/1.1" 201 234
[2023-05-17 12:24:55,259] [django.server::log_message::161] [INFO] "POST /api/predictions/ HTTP/1.1" 201 234
[2023-05-17 12:27:15,945] [django.server::log_message::161] [INFO] "POST /api/predictions/ HTTP/1.1" 201 241
[2023-05-17 12:27:15,945] [django.server::log_message::161] [INFO] "POST /api/predictions/ HTTP/1.1" 201 241
[2023-05-17 12:40:58,170] [django.server::log_message::161] [INFO] "GET /api/webhooks?project=18 HTTP/1.1" 200 257
[2023-05-17 12:40:58,170] [django.server::log_message::161] [INFO] "GET /api/webhooks?project=18 HTTP/1.1" 200 257
[2023-05-17 12:41:06,119] [django.server::log_message::161] [INFO] "POST /api/predictions/ HTTP/1.1" 201 241
[2023-05-17 12:41:06,119] [django.server::log_message::161] [INFO] "POST /api/predictions/ HTTP/1.1" 201 241
[2023-05-17 12:42:54,085] [django.server::log_message::161] [INFO] "GET /api/tasks/24755?project=18 HTTP/1.1" 200 991
[2023-05-17 12:42:54,085] [django.server::log_message::161] [INFO] "GET /api/tasks/24755?project=18 HTTP/1.1" 200 991
[2023-05-17 12:47:35,514] [django.server::log_message::161] [INFO] "GET /api/predictions/25116 HTTP/1.1" 200 241
[2023-05-17 12:47:35,514] [django.server::log_message::161] [INFO] "GET /api/predictions/25116 HTTP/1.1" 200 241
```