config.yaml: Use same release specified in devices.yaml for aum offline upgrade branch test

The devices.yaml configuration has been updated so that we use v2023.3
images as a first stage in tests. For whatever reason, the image used
for the aum offline upgrade branch tests don't use this configuration,
but separate configuration in config.yaml. This is currently set to
v2022.0.

We had an issue that the RPi4 images were being produced with a smaller
boot partition than other targets. This was resulting in the space
running out on the boot partition in some tests for RPi4. This issue was
fixed, with the partitions being adjusted to be the same size as other
targets, and backported to v2024 and v2023.

We are seeing issues with the boot partition running out persisting for
the aum offline upgrade branch tests as it's using v2022 as it's first
stage image, which is no longer a supported release and as such didn't
receive the tweaks to the partition sizing.

Update the release used for this test to v2023.3 in line with other
tests.

Signed-off-by: Martyn Welch <martyn.welch@collabora.com>