fix: Handle unset cookies correctly

[larseggert]

Fixes #5015

[codecov]

Codecov Report

Merging #5023 (a1b44fa) into main (570bd14) will decrease coverage by 0.01%.
The diff coverage is 98.24%.

@@            Coverage Diff             @@
##             main    #5023      +/-   ##
==========================================
- Coverage   88.47%   88.47%   -0.01%     
==========================================
  Files         296      296              
  Lines       39818    39852      +34     
==========================================
+ Hits        35230    35259      +29     
- Misses       4588     4593       +5     

Impacted Files	Coverage Δ
ietf/meeting/views.py	90.69% <98.00%> (+0.12%)	⬆️
ietf/iesg/agenda.py	92.06% <100.00%> (+0.06%)	⬆️
ietf/utils/text.py	86.58% <100.00%> (+0.60%)	⬆️
ietf/meeting/templatetags/proceedings_filters.py	88.23% <0.00%> (-5.89%)	⬇️
ietf/meeting/models.py	85.91% <0.00%> (-0.59%)	⬇️
ietf/group/models.py	92.30% <0.00%> (-0.37%)	⬇️
ietf/group/utils.py	94.17% <0.00%> (+0.44%)	⬆️

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.