vscode.executeCodeActionProvider results seem to be missing their `isPreferred` property

[ypresto]

Issue Type: Bug

isPreferred version of #45124.
isPreferred property in result of vscode.executeCodeActionProvider is always undefined.

While it is not required to execute command, but is useful information.
(diagnostics is also missing but I ignored it because it is relatively large structure and more costly to implement type converters.)