Can not disable Use pre-signed URLs for GCS Source Storage

[nader-bitstrapped-com]

When creating or editing a GCS Source Storage, disabling the Use pre-signed URLs does not work.

To Reproduce

1. Go to Project -> Setting -> Cloud Storage -> Add Source Storage -> GCS
2. Fill the form and disable the Use pre-signed URLs toggle button.
3. Save the form.
4. Click on the three dots and Edit.
5. Use pre-signed URLs is enabled.

Expected behavior
Use pre-signed URLs should be disabled.

Screenshots

Environment (please complete the following information):

• Docker
• Label Studio Version 1.0.2

Additional context
Value sent to backend when form is submitted with Use pre-signed URLs disabled:

{
  "project": "3",
  "bucket": "test",
  "regex_filter": ".*",
  "use_blob_urls": true,
  "presign_ttl": "1"
}

Value sent to backend when with the Use-pre-signed URLs enabled:

{
  "project": "3",
  "bucket": "test",
  "regex_filter": ".*",
  "use_blob_urls": true,
  "presign": "true",
  "presign_ttl": "1"
}

Seems like when the toggle button is disabled "presign": "false" is not sent. Might be a frontend regression.

[nader-bitstrapped-com]

I just tried this with 1.1.0 and issue still persists.