Closes#16876
We only ever showed parsing errors, but not if something failed to
deserialize.
Basically, if you had a stray `,` somewhere, we'd show a notification
for user errors, but only squiggly lines if you had a `[]` instead of a
`{}`.
The squiggly lines would only show up when there were schema errors.
In the case of `formatter` settings, for example, if someone put in a
`{}` instead of `[]`, we'd never show anything.
With this change we always show a notification if parsing user or
project settings fails.
(Right now, the error message might still be bad, but that's a separate
change)
Release Notes:
- Added a notification to warn users if their user settings or
project-local settings failed to deserialize.
Demo:
https://github.com/user-attachments/assets/e5c48165-f2f7-4b5c-9c6d-6ea74f678683
ace4d5185d