Use busybox dd

This test rely in dd command to be available in the image. Unfortunately, in v2023 dd is only provided by busybox and the link is not created. Since v2023 is an old stable release, instead of create a new package to handle the link as it is done with other missing commands (grep, sed, etc) just fix the test.

infrastructure/apertis-issues#574 (closed)

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