flatpak: Add test for installing extensions when updating an app

When updating an app, if its runtime needs an extension and it's missing
(e.g. because it wasn't correctly installed before), then install the
extension while updating the app too.
1 job for wip/jrocha/pull-runtime-related-refs-stable in 4 minutes and 13 seconds (queued for 5 seconds)
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Status Job ID Name Coverage
  Build
passed #59076
build-gnome-software

00:04:13