qa: run e2e test on centos only

it's a regression introduced by the restrcuture of the test suites,
let's pin the test to CentOS8.

See-also: https://tracker.ceph.com/issues/49638
Signed-off-by: Kefu Chai <kchai@redhat.com>

diff --git a/qa/suites/rados/dashboard/centos_8.2_kubic_stable.yaml b/qa/suites/rados/dashboard/centos_8.2_kubic_stable.yaml
new file mode 120000 (symlink)
index 0000000..3afeed7
--- /dev/null
+++ b/qa/suites/rados/dashboard/centos_8.2_kubic_stable.yaml
@@ -0,0 +1 @@
+.qa/distros/podman/centos_8.2_kubic_stable.yaml
\ No newline at end of file