Consume horizon tempest test from tempest master

As disscussed in Wallaby PTG[1], QA and Horizon team
decided to move the horizon dashboard test from tempest-horizon
to Tempest. As next step, we can remove the tempest-horizon
plugin which will ease the maintaince of horizon tempest test.

Depends-On: https://review.opendev.org/c/openstack/tempest/+/771727
Change-Id: I0dc58db29825446381c319ec904e8bf225b210e1

.zuul.d/tempest-and-integrated.yaml

@@ -35,7 +35,6 @@
     required-projects: &base_required_projects
       - name: openstack/horizon
       - name: openstack/tempest
-      - name: openstack/tempest-horizon
     irrelevant-files: &base_irrelevant_files
       - ^.*\.rst$
       - ^doc/.*$
@@ -56,9 +55,7 @@
         horizon: true
         tempest: true
       tempest_concurrency: 2
-      tempest_test_regex: horizon
-      tempest_plugins:
-        - tempest-horizon
+      tempest_test_regex: test_dashboard_basic_ops
       tox_envlist: all
 
 - job: