test: Adjust TestConnection.testTls for centos-9-bootc

That image does not have certmonger (and we don't need it - we already
run the test on CentOS 9 stream rpm).

test/verify/check-connection

@@ -470,7 +470,7 @@ class TestConnection(testlib.MachineCase):
 
         # certmonger generated certificate; asciibetically later than the above
         # not all images have certmonger
-        if m.image not in ["debian-stable", "debian-testing", "fedora-coreos", "arch"]:
+        if m.image not in ["debian-stable", "debian-testing", "fedora-coreos", "arch", "centos-9-bootc"]:
             hostname = m.execute("hostname --fqdn").strip()
             m.execute(f"getcert request -f /etc/cockpit/ws-certs.d/monger.cert -k /etc/cockpit/ws-certs.d/monger.key -D {hostname} --ca=local --wait")
             self.addCleanup(m.execute, "getcert stop-tracking -f /etc/cockpit/ws-certs.d/monger.cert")