Improve sorting of quick fixes

[mueller-ma]

When using this extension together with the ruff extension, the order of quick fixes isn't optimal. For undefined variables VS Code suggests to disable checking for undefined variables as first one and to add a missing import as second.

This has been reported to Ruff, but it seems that they can't sort the quick fixes: astral-sh/ruff-vscode#624

Maybe pylance could set isPreferred for the add import quick fix, so it's listed as first one? https://vscode-api.js.org/classes/vscode.CodeAction.html#isPreferred