Setting to control original line numbers shown in the inline diff view

## Describe the feature you'd like

When the diff editor uses the **inline view** (e.g. switching a Git diff to `Inline View`), it currently renders a narrow column with the **original (before-edit) line numbers** to the left of the modified content. This differs from GitHub Copilot's inline diff, which drops that column and shows only the after-edit line numbers.

I'd like a user setting to control this behavior. It should default to hiding the original line numbers in the inline view, with an option to bring them back.

## Proposed behavior

- New setting `diffEditor.hideOriginalLineNumbers` (boolean).
- Default: `true`, meaning the inline diff view does not show the line numbers of the file before changes.
- Setting it to `false` restores the before/after line numbers in the inline view.
- Only affects the inline view; the side-by-side view is unchanged.

A prototype is implemented in PR https://github.com/microsoft/vscode/pull/329899.

## Describe alternatives you've considered

Keeping the current behavior and only adding an opt-out setting (default `false`) — but the request is to make hiding the original line numbers the default in the inline view.