feat: handle receivers counter race condition

[Chadys]

The race condition when updating a counter can be solved by simply retrying the update operation if the creation fails because it was created faster from somewhere else.
(PS: this is my last one in the set of contributions I planned to make in a row)

[codecov]

Codecov Report

Merging #4290 (d6e521b) 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    #4290      +/-   ##
==========================================
+ Coverage   88.28%   88.36%   +0.07%     
==========================================
  Files         293      293              
  Lines       16046    16094      +48     
==========================================
+ Hits        14166    14221      +55     
+ Misses       1880     1873       -7     

Files	Coverage Δ
src/oscar/apps/analytics/receivers.py	91.07% <100.00%> (ø)

... and 9 files with indirect coverage changes