qa/distros: add centos 9 stream back to supported distros

https://github.com/ceph/ceph/pull/66055 replaced centos_latest with
rpm_latest but didn't add centos_9 back. we want to test both

Signed-off-by: Casey Bodley <cbodley@redhat.com>

diff --git a/qa/distros/supported-random-distro$/centos_9.stream.yaml b/qa/distros/supported-random-distro$/centos_9.stream.yaml
new file mode 120000 (symlink)
index 0000000..38fea53
--- /dev/null
+++ b/qa/distros/supported-random-distro$/centos_9.stream.yaml
@@ -0,0 +1 @@
+../all/centos_9.stream.yaml
\ No newline at end of file

diff --git a/qa/distros/supported/centos_9.stream.yaml b/qa/distros/supported/centos_9.stream.yaml
new file mode 120000 (symlink)
index 0000000..38fea53
--- /dev/null
+++ b/qa/distros/supported/centos_9.stream.yaml
@@ -0,0 +1 @@
+../all/centos_9.stream.yaml
\ No newline at end of file