OSIS-796 When checking perm to cancel proposal check that proposal is not None
OSIS-796 When checking perm to cancel proposal check that proposal is not None

uclouvain/osis_louvain,uclouvain/osis_louvain,uclouvain/osis,uclouvain/OSIS-Louvain,uclouvain/osis,uclouvain/osis,uclouvain/OSIS-Louvain,uclouvain/osis_louvain,uclouvain/OSIS-Louvain,uclouvain/osis