plugin OXPS: fix triggers return values:

rel 381

sat/plugins/plugin_sec_oxps.py

@@ -694,9 +694,9 @@ class PubsubEncryption:
         items: List[domish.Element],
         rsm_response: rsm.RSMResponse,
         extra: Dict[str, Any],
-    ) -> None:
+    ) -> bool:
         if not extra.get(C.KEY_DECRYPT, True):
-            return
+            return True
         if service is None:
             service = client.jid.userhostJID()
         shared_secrets = None
@@ -719,7 +719,7 @@ class PubsubEncryption:
                         log.warning(
                             f"No known shared secret for {node_uri}, can't decrypt"
                         )
-                        return
+                        return True
                 try:
                     shared_secret = shared_secrets[secret_id]
                 except KeyError:
@@ -737,6 +737,7 @@ class PubsubEncryption:
                 item.children.clear()
                 item.addChild(decrypted_elt)
                 extra.setdefault("encrypted", {})[item["id"]] = {"type": NS_OXPS}
+        return True
 
     async def _message_received_trigger(
         self,