fix(mock): correct query param mocks

[ecrupper]

When trying to test a 0 for the query param, it won't add it to the url string here where we build the query string in the SDK. This change makes sure the 500 response is actually testable.

[codecov]

Codecov Report

Merging #866 (89ba5f3) into main (e8bdb15) will decrease coverage by 0.03%.
The diff coverage is n/a.

❗ Current head 89ba5f3 differs from pull request most recent head 8d6b8bf. Consider uploading reports for the commit 8d6b8bf to get more accurate results

@@            Coverage Diff             @@
##             main     #866      +/-   ##
==========================================
- Coverage   72.07%   72.04%   -0.03%     
==========================================
  Files         312      310       -2     
  Lines       13051    12930     -121     
==========================================
- Hits         9407     9316      -91     
+ Misses       3188     3168      -20     
+ Partials      456      446      -10     

see 2 files with indirect coverage changes