Force a reinstall if an existing hardened bundle is present.

More tasks related to #21912 (closed).

Since there's no good way for sandboxed-tor-browser to handle channels being removed, the solution I'm going for is to force a re-install if an existing hardened bundle is present.

Some minor UI work is probably required since this will obliterate user data.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information