## Description
Backend CI no longer flakes when the conversation FAQ grouping-lock spec
runs after Rails has reloaded application constants.
The job already raises the intended lock-acquisition error and prevents
concurrent suggestion generation. This updates the assertion to compare
the error class name, preserving that behavior without depending on a
reload-sensitive Ruby `Class` object.
The failure was reproduced in [CircleCI backend job
171299](https://app.circleci.com/pipelines/github/chatwoot/chatwoot/116560/workflows/efcee2f1-5af8-4121-82c3-920002dc420b/jobs/171299).
## Type of change
- [x] Bug fix (non-breaking change which fixes an issue)
## How Has This Been Tested?
The isolated job spec passes, the exact 18-way CircleCI shard selection
passes all 442 examples, and the changed spec passes Ruby lint.
## Checklist:
- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] My changes generate no new warnings
- [x] New and existing unit tests pass locally with my changes
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