Unable to enable snowflake in new browser embed page URL

The current code is now automatically built and deployed to https://embed-snowflake.staging.torproject.net and https://embed-snowflake.torproject.org (prod).

Unfortunately, it doesn't work. Clicking the toggle button does nothing, the Snowflake client doesn't start.

This is blocking updates being rolled out to snowflake.torproject.org since the old, working embedded client was deployed there manually in the meantime.