[infrastructure] Certify the relay UBI image on release

Releases certify the UBI images through redhat-certify.yml, which only
lists the client, proxy and combined server, so a released relay UBI
image would never reach the Red Hat catalog.

Add relay to the component list and the manual dispatch options. Its
Partner Connect ID comes from REDHAT_CERT_ID_RELAY, which must exist
before this merges: the resolve step fails the whole run when any
component's variable is missing.

.github/workflows/redhat-certify.yml

@@ -33,6 +33,7 @@ on:
           - client-rootless
           - reverse-proxy
           - netbird-server
+          - relay
       version:
         description: "Released version, e.g. v0.80.0"
         type: string
@@ -68,6 +69,7 @@ jobs:
             "client-rootless ghcr.io/netbirdio/netbird -rootless-ubi"
             "reverse-proxy ghcr.io/netbirdio/reverse-proxy -ubi"
             "netbird-server ghcr.io/netbirdio/netbird-server -ubi"
+            "relay ghcr.io/netbirdio/relay -ubi"
           )
           matrix="[]"
           missing=()