Disable HTTP 2 in flapak tests on SDK

Following the same approach used at image generation, disable HTTP 2 in
flatpak to overcome connections issues as OSTree does not support retries.

infrastructure/apertis-image-recipes!612
https://github.com/ostreedev/ostree/issues/2570
infrastructure/apertis-issues#436



Signed-off-by: Walter Lozano <walter.lozano@collabora.com>

test-cases/flatpak-run-demo-hmi-app.yaml

@@ -20,6 +20,8 @@ run:
   steps:
     - "Add the Apertis Flatpak repository (only needed on SDK images)"
     - $ flatpak --user remote-add --if-not-exists apertis https://images.apertis.org/flatpak/repo/apertis.flatpakrepo
+    - "Force HTTP 1.1 as OSTree does not support retries over HTTP 2 (only needed on SDK images)"
+    - $ ostree --repo=/home/user/.local/share/flatpak/repo config set 'remote "apertis".http2' false
     - "Install the Flatpak example application (only needed on SDK images)"
     - $ flatpak --user install --reinstall org.apertis.hmi.gnome_font_viewer//${APERTIS_RELEASE}
     - "On the agl-compositor click on the menu icon"