CI: Drop Zed testing as it is unmaintained

Change-Id: I3ac1755762191efb7450087e079ef24c8d296333

.zuul.d/jobs_zed.yaml

@@ -1,23 +0,0 @@
----
-- job:
-    name: magnum-tempest-plugin-tests-api-zed
-    parent: magnum-tempest-plugin-tests-api-base
-    nodeset: openstack-single-node-focal
-    override-checkout: stable/zed
-    vars:
-      devstack_localrc:
-        MAGNUM_GUEST_IMAGE_URL: https://builds.coreos.fedoraproject.org/prod/streams/stable/builds/35.20220116.3.0/x86_64/fedora-coreos-35.20220116.3.0-openstack.x86_64.qcow2.xz
-      devstack_local_conf:
-        test-config:
-          $TEMPEST_CONFIG:
-            magnum:
-              image_id: fedora-coreos-35.20220116.3.0-openstack.x86_64
-
-- project-template:
-    name: magnum-tempest-plugin-jobs-zed
-    check:
-      jobs:
-        - magnum-tempest-plugin-tests-api-zed
-    gate:
-      jobs:
-        - magnum-tempest-plugin-tests-api-zed

.zuul.d/project.yaml

@@ -5,6 +5,5 @@
       - check-requirements
       - tempest-plugin-jobs
       - magnum-tempest-plugin-jobs-master
-      - magnum-tempest-plugin-jobs-zed
       - magnum-tempest-plugin-jobs-2023-1
       - magnum-tempest-plugin-jobs-2023-2