Backport Sxmo 1.15.1 to v23.12 (MR 4605)
The testing phase is almost over, but it will still be some more time until the release. Given that Sxmo 1.15.x just came out after 3.19-stable was branched in aports.git by chance, backport the new Sxmo release to v23.12 as discussed with the Sxmo team.