Add new command for positron.executeCodeInConsole to be used by extensions that handles uri, position, next position

[juliasilge]

• Addresses Statement range provider does not work in Quarto's visual editor #7709
• Related to Code mockup for proposal to change workbench.action.positronConsole.executeCode in Positron quarto-dev/quarto#867

I've been collaborating with @vezwork on how to get more language features hooked up in Quarto's visual editor, and we think this is what we need for the Quarto custom editor interface to be able to send code statement-by-statement to the console. Over in the Quarto extension, we can now do something like:

  const nextPosition = await vscode.commands.executeCommand(
      'positron.executeCodeInConsole',
      'python',                              // language ID
      vscode.Uri.file('/path/to/script.py'), // document URI
      new vscode.Position(5, 0)              // position
  ) as vscode.Position | undefined;

What we get back is the next position to move the cursor to, in Quarto's case for the virtual doc underlying the visual editor.

It's a little weird to now have two commands, both the old workbench.action.positronConsole.executeCode and the new positron.executeCodeInConsole, but now that we're dealing with positions (and less so, URIs) we need to use the converters that we have access to in src/vs/workbench/api/common/extHostApiCommands.ts. I think I'd argue they do different enough things that this is OK? Although you can now technically call workbench.action.positronConsole.executeCode with a uri and position, but they would have to be the internal main process versions of those; this feels somewhat weird. Is it worth doing more refactoring here to make this nicer?

@:sessions
@:console

Release Notes

New Features

• Added new command positron.executeCodeInConsole for extensions to execute code for a given language, URI, and position (such as for the Quarto visual editor)

Bug Fixes

• N/A

QA Notes

Once we get changes merged on both the Positron and Quarto sides, you should be able to execute multi-line statements in the console from the visual editor. Once we get further along, I can share more detailed examples

[github-actions]

E2E Tests 🚀
This PR will run tests tagged with: @:critical @:sessions @:console

^{readme  valid tags}

[juliasilge]

The reason we need a new command over here is to use the type converters for position, to get the position type that extensions can use.

[juliasilge]

We're dealing with URIs for the visual editor, and don't want to mess with the editor itself.

[juliasilge]

The visual editor needs to know the next position directly, because it manages its own cursor and selection and such.

[juliasilge]

This command is registered here so we can make one in extHostApiCommands.ts. I want to note that right now these are not optional arguments for using with this command. Good? Bad? We could do these arguments like URI | undefined if we want.