This indicates the current state, lets the user exit without changing
state, and lets the user change state any time they want.

This change also improves RTL support in the telemetry modal.

The playground now displays this on startup when in Scratch Desktop
simulation mode.

Also just cleaner formatting of the connect in the `errorBoundary` container

- Auditing color CSS and componet CSS to make consistent.
- Made a first pass of changes to increase contrast to elements that previously were problematic

- reduced the load time of the preview modal assets
- changed cursor to ‘pointer’ for modal buttons

- implements welcome to the preview modal, and unsupported browser modal.
- will need assets updated in Jan.