Investigation Consider turning off the auto updates for airgap installations

Is your feature request related to a problem? Please describe

It was discussed some time ago in https://github.com/podman-desktop/podman-desktop/issues/15384, where we were considering if airgap installation should offer to update to a newer version or not.

Since https://github.com/podman-desktop/podman-desktop/issues/16035 was implemented, we have a way to turn off the update by default (can be enabled by user).

Describe the solution you'd like

So consider setting the default value for the preference property preferences.update.appUpdate to false when it is an airgap installation AIRGAP_DOWNLOAD=1 -> this is set during build time.

Describe alternatives you've considered

Things to consider:

1. airgap environment itself might not have access to internet and so no update is offered
2. airgap installation is handled by managed configuration not to update in the whole organization
3. Airgap installation does not have option to update to newer version of airgap installation. This might be actually an issue, but to resolve, we need to introduce channels (https://github.com/podman-desktop/podman-desktop/issues/18190) or change the location for updates -> to set a different update.url which might be a little problem with gh provider.

Additional context

No response