Feature: add optional Wayland support

Currently, if I want to run VSCode in native Wayland mode, I need to either (1) launch from the terminal and pass ozone flags or (2) modify the desktop file and add those flags. Neither method is particularly good.

I propose that this this VSCode flatpak should [follow in the steps of the Discord flatpak](https://github.com/flathub/com.discordapp.Discord/commit/a2f7a449af1af18a36e2547a2658cf5be5e986d5) and add an optional native Wayland mode. With the Discord flatpak, it by default only comes with X11 access. But if you grant it Wayland access, it will automatically launch in native Wayland mode.

Inspect the repository's Flatpak manifest and compare the proposed behavior with the linked Discord Flatpak commit. Verify how optional Wayland access is represented and confirm that granting it launches VSCode in native Wayland mode while the default remains X11.

Written by the indexing model from the issue text.