refactor: Simplify tests and comply with StandardJS style

[jennifer-richards]

Use === instead of ==, except where it's used to match both null and undefined. (I think just null is enough because both cookies.get() and Storage.getItem() return null when they have no data, but no harm in being liberal.)

@larseggert may want to look to be sure I didn't break this, but I think it's equivalent.

[codecov]

Codecov Report

Merging #5026 (46c5691) into main (570bd14) will decrease coverage by 0.03%.
The diff coverage is 98.24%.

@@            Coverage Diff             @@
##             main    #5026      +/-   ##
==========================================
- Coverage   88.47%   88.45%   -0.03%     
==========================================
  Files         296      296              
  Lines       39818    39852      +34     
==========================================
+ Hits        35230    35250      +20     
- Misses       4588     4602      +14     

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/submit/checkers.py	73.60% <0.00%> (-3.05%)	⬇️
ietf/meeting/models.py	85.91% <0.00%> (-0.59%)	⬇️
ietf/group/models.py	92.30% <0.00%> (-0.37%)	⬇️
ietf/utils/draft.py	71.54% <0.00%> (-0.21%)	⬇️
ietf/doc/views_search.py	89.23% <0.00%> (ø)

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