d/merge-vulkan-driver-manifests.sh: Remove library_arch from JSON manifests
d/merge-vulkan-driver-manifests.sh: Remove library_arch from JSON manifests
Since 25.2.1 they differ slightly between architectures, having added
a library_arch field. That's the only difference, so for now just
remove it, while a longer-term solution is discussed on mesa/mesa#13745.
Closes: #1110523