[COST-4844] Serializer update for ordering by storageclass

[myersCody]

Jira Ticket

COST-4844

Description

This change will allow you to order by storageclass when grouping by storageclass

Testing

http://localhost:8000/api/cost-management/v1/reports/openshift/volumes/?group_by%5Bstorageclass%5D=*&order_by%5Bstorage_class%5D=desc

Release Notes

• proposed release note

* [COST-4844](https://issues.redhat.com/browse/COST-4844) Tweak serializer for storageclass order by

[myersCody]

/retest

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.2%. Comparing base (011ec69) to head (f33ec89).

Additional details and impacted files

@@          Coverage Diff          @@
##            main   #5174   +/-   ##
=====================================
  Coverage   94.2%   94.2%           
=====================================
  Files        376     376           
  Lines      31230   31233    +3     
  Branches    3725    3727    +2     
=====================================
+ Hits       29410   29414    +4     
+ Misses      1161    1158    -3     
- Partials     659     661    +2     

[myersCody]

/retest