Keep the 5.1 branch buildable

[Alvin Wong]

Hi,

On 12/1/2023 18:42, Halla Rempt wrote:
> Because krita/5.1 is still our designated stable branch, we need to keep it green both on binary factory and in CI. I'm not sure what caused the failure of https://binary-factory.kde.org/job/Krita_Stable_Appimage_Build/ -- maybe it was just a glitch, so I've restarted that, but there's also https://invent.kde.org/graphics/krita/-/jobs/695658#L6025.

For the GitLab CI failure, https://bugs.kde.org/show_bug.cgi?id=463889 
applies. The CI image must have been updated recently and that bumped 
libheif to the broken version. Upstream libheif has released 1.14.2 to 
specifically fix the issue.