fix: typo in has_children value and tests of annotated list extra info

[Chadys]

There was a typo in has_children computation, the wrong variable is used for the comparison. I also added a test for get_annotated_list's num_to_close and has_children values.

[codecov]

Codecov Report

Merging #4284 (fda6d46) into master (204b9a7) will increase coverage by 0.07%.
Report is 11 commits behind head on master.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4284      +/-   ##
==========================================
+ Coverage   88.28%   88.36%   +0.07%     
==========================================
  Files         293      293              
  Lines       16046    16095      +49     
==========================================
+ Hits        14166    14222      +56     
+ Misses       1880     1873       -7     

Files	Coverage Δ
src/oscar/templatetags/category_tags.py	94.44% <100.00%> (+0.07%)	⬆️

... and 9 files with indirect coverage changes