feat: add error on response for user-creation for graphkb #1742

All 565 tests pass in 2m 44s

    1 files ±0   62 suites ±0 2m 44s ⏱️ -1s
565 tests ±0 565 ✔️ ±0 0 💤 ±0 0 ❌ ±0
562 runs ±0 562 ✔️ ±0 0 💤 ±0 0 ❌ ±0

Results for commit c82ee26. ± Comparison against ancestor commit 0a6f197.