Incorrect defaults for COMMUNITIES_CUSTOM_FIELDS (and ui) in invenio_communities/config.py

[mesemus]

Package version (if known): all releases

Describe the bug

The default for COMMUNITIES_CUSTOM_FIELDS in

invenio-communities/invenio_communities/config.py

Line 228 in b4dcd46

COMMUNITIES_CUSTOM_FIELDS = {}

is an empty dict, but should be a list (even written in the usage inside docstring). Dtto for COMMUNITIES_CUSTOM_FIELDS_UI

Expected behavior

Should be an array, not a dict