Dont fail on urn:xmpp:hashes:1

Fixes #9514

gajim/common/app.py

@@ -148,6 +148,7 @@ socks5queue = None
 gupnp_igd = None
 
 gajim_identity = {'type': 'pc', 'category': 'client', 'name': 'Gajim'}
+
 gajim_common_features = [nbxmpp.NS_BYTESTREAM, nbxmpp.NS_SI, nbxmpp.NS_FILE,
     nbxmpp.NS_MUC, nbxmpp.NS_MUC_USER, nbxmpp.NS_MUC_ADMIN, nbxmpp.NS_MUC_OWNER,
     nbxmpp.NS_MUC_CONFIG, nbxmpp.NS_COMMANDS, nbxmpp.NS_DISCO_INFO, 'ipv6',

gajim/common/jingle_session.py

@@ -445,6 +445,8 @@ class JingleSession:
             if child.getName() == 'checksum':
                 hash_ = child.getTag('file').getTag(name='hash',
                                                     namespace=nbxmpp.NS_HASHES_2)
+                if hash_ is None:
+                    continue
                 algo = hash_.getAttr('algo')
                 if algo in nbxmpp.Hashes2.supported:
                     file_props = FilesProp.getFileProp(self.connection.name,