Web terminals don't work in Safari: `ReferenceError: can't find variable: TextDecoder`
Summary
Web terminals raise a JavaScript error if viewed in Safari
Steps to reproduce
Navigate to a .../terminal URL in safari
Expected behavior
Working terminal
Actual behavior
ReferenceError: can't find variable: TextDecoder
Relevant logs and/or screenshots
Possible fixes
We could add a polyfill like https://github.com/inexorabletash/text-encoding perhaps? This seems easier than conditionally using the base64.terminal.gitlab.com subprotocol.