Complement full-cluster-secret-store oracle example (#2731)

Add namespace to secretRef.privatekey and secretRef.fingerprint in oracle provider example at full-cluster-secret-store.yaml to avoid confusion like in #2727

Signed-off-by: antoniolago <45375617+antoniolago@users.noreply.github.com>

docs/snippets/full-cluster-secret-store.yaml

@@ -131,10 +131,12 @@ spec:
             # The secret that contains your privatekey
             name: oci-secret-name
             key: privateKey
+            namespace: example-namespace
           fingerprint:
             # The secret that contains your fingerprint
             name: oci-secret-name
             key: fingerprint
+            namespace: example-namespace
 
     # (TODO): add more provider examples here