Revert bumping skyline images for Ubuntu Noble

An upper-constraints update on master branch[1] caused python module
``pydantic`` version conflict.
This blocks building new images for skyline-apiserver.

Keeping Skyline images from 25th April 2025 until [2] is merged.

[1] https://review.opendev.org/c/openstack/requirements/+/943089
[2] https://review.opendev.org/c/openstack/skyline-apiserver/+/949524

Author: seunghun1ee

etc/kayobe/kolla-image-tags.yml

@@ -19,3 +19,4 @@ kolla_image_tags:
     rocky-9: master-rocky-9-20250502T080944
   skyline:
     rocky-9: master-rocky-9-20250425T091159
+    ubuntu-noble: master-ubuntu-noble-20250425T091159