fix: Guard against null form-group around name fields in session_details_form.js

[jennifer-richards]

Fixes #5174

This JS file supports the ietf.meeting.forms.SessionDetailsForm form. In normal use, the form is rendered with its inputs (including name and short) inside div.form-group elements. However, the form is also reused in the secr.sreq app, where the fields are rendered ad hoc. The short field was recently added as an always-hidden field not contained inside a div.form-group, causing the JS code to fail. As a result, the visibility of various fields was not updated, including the purpose/type fields complained about in #5174.

[codecov]

Codecov Report

Merging #5175 (359f6cc) into main (f9c2376) will decrease coverage by 0.01%.
The diff coverage is 90.27%.

@@            Coverage Diff             @@
##             main    #5175      +/-   ##
==========================================
- Coverage   88.54%   88.53%   -0.01%     
==========================================
  Files         295      295              
  Lines       40046    40050       +4     
==========================================
+ Hits        35458    35460       +2     
- Misses       4588     4590       +2     

Impacted Files	Coverage Δ
ietf/doc/urls.py	100.00% <ø> (ø)
ietf/doc/views_doc.py	91.53% <ø> (+0.15%)	⬆️
ietf/api/views.py	89.44% <89.55%> (-0.03%)	⬇️
ietf/api/urls.py	100.00% <100.00%> (ø)
ietf/sync/discrepancies.py	100.00% <100.00%> (ø)
ietf/utils/text.py	85.97% <0.00%> (-1.22%)	⬇️
ietf/doc/views_search.py	89.02% <0.00%> (-0.21%)	⬇️
ietf/nomcom/utils.py	91.54% <0.00%> (+0.24%)	⬆️

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