Schema validation error: '' does not match '^[a-z]{2,3}(?:-[a-zA-Z]+)?$'

[sentry-io]

Sentry Issue: STUDIO-HTX

Schema validation error: '' does not match '^[a-z]{2,3}(?:-[a-zA-Z]+)?$'

Failed validating 'pattern' in schema['properties']['topics']['items']['properties']['language']:
    {'type': 'string',
     'description': 'Language code from '
                    'https://github.com/learningequality/le-utils/blob/main/le_utils/resources/languagelookup.json',
     'pattern': '^[a-z]{2,3}(?:-[a-zA-Z]+)?$'}

On instance['topics'][0]['language']:
    ''

The request objects is as below. The language passed is empty, triggering the error.

{
  "metadata": {
    "channel_id": "8121f04e-fde5-44e4-b470-c229b5dffcf4"
  },
  "topics": [
    {
      "ancestors": [...],
      "description": "",
      "id": "a6c7b497-49fc-47fa-8e2c-70b36fb1c893",
      "language": "",
      "title": "Algebra"
    }
  ]
}