testing/electron: add flag configs, run on wayland if possible
electron v19.0.10 backports the --ozone-platform-hint
flag from chromium (see: https://releases.electronjs.org/release/v19.0.10)
this MR adds a launcher script similar to what chromium has, and creates a default config with --ozone-platform-hint=auto
added, which makes apps run on wayland for wayland users by default