[COST-5796] correctly log exception outside log_json function

[djnakabaale]

Jira Ticket

COST-5796

Description

This change is a followup on #5431, to correctly pass exception outside log_json function.

Testing

1. Checkout Branch
2. Restart Koku
3. Run unit test and see log message

python3 koku/manage.py test koku.test_middleware.IdentityHeaderMiddlewareTest.test_create_customer_integrity_error_existing_customer

Release Notes

• correctly log exception outside log_json function

* [COST-5796](https://issues.redhat.com/browse/COST-5796) correctly log exception outside log_json function

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.1%. Comparing base (66082b8) to head (8e0190d).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #5448     +/-   ##
=======================================
- Coverage   94.2%   94.1%   -0.0%     
=======================================
  Files        370     370             
  Lines      31550   31550             
  Branches    3381    3381             
=======================================
- Hits       29706   29704      -2     
- Misses      1198    1199      +1     
- Partials     646     647      +1