add event id to logcontext when handling incoming PDUs

changelog.d/10936.misc

@@ -0,0 +1 @@
+Include the event id in the logcontext when handling PDUs received over federation.

synapse/federation/federation_server.py

@@ -1008,7 +1008,10 @@ async def _process_incoming_pdus_in_room_inner(
             async with lock:
                 logger.info("handling received PDU: %s", event)
                 try:
-                    await self._federation_event_handler.on_receive_pdu(origin, event)
+                    with nested_logging_context(event.event_id):
+                        await self._federation_event_handler.on_receive_pdu(
+                            origin, event
+                        )
                 except FederationError as e:
                     # XXX: Ideally we'd inform the remote we failed to process
                     # the event, but we can't return an error in the transaction