fix: zero entire public key array instead of only first byte (#9619)

src/modules/AdminModule.cpp

@@ -391,7 +391,7 @@ bool AdminModule::handleReceivedProtobuf(const meshtastic_MeshPacket &mp, meshta
             node->has_device_metrics = false;
             node->has_position = false;
             node->user.public_key.size = 0;
-            node->user.public_key.bytes[0] = 0;
+            memset(node->user.public_key.bytes, 0, sizeof(node->user.public_key.bytes));
             saveChanges(SEGMENT_NODEDATABASE, false);
         }
         break;