Bug 32121: (QA follow-up) Use error_code rather than key

Bug 32121: (QA follow-up) Use error_code rather than key

We semi-recently introduced error_code into our error object to allow
for translation and code paths for different errors without having to
rely on long description string matches.

This QA follow-up converts the existing match and new 'key' fields
introduced in this patchset to use the updated 'error_code' key.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>