Follow-up to df40ee7216
- Restore opening of non-HTTP URL schemes in link attachments
- Remove scheme whitelist for link attachments, since it's not enforced
via the API anyway and we prompt before an external application is
opened. Instead, just block a few schemes (e.g., 'javascript') from
launching.
TODO:
- Provide some way to change/reset an application association if the
user checks the box to automatically open that scheme.
- Show an error message if a link attachment with an invalid URL is
double-clicked
3d2afa9c7f