Error persist after the file/project is closed

[billti]

I was working on a file with Adaptive profile set, I then opened Shor.qs briefly to look up something, which has an error in Adaptive, but then after closing Shor.qs, the error persists with no way to remove it (other than reload VS Code window).

Once the final file in a project is closed (or THE file in single file mode) we should clear out the errors from the project.

[sezna]

This is possibly related to #1781 and will require further investigation. @billti, could you see if this is still an issue with that extension disabled?