ci(api-review-gate): let a sizeable fork change reach the approval check

api-gate exits 2 to report a sizeable change, and the runner runs a step
without an explicit shell as bash -e. The fork detect step switched
errexit off only after reading the exit code, so the first failing
command ended the step with 2 before sizeable=true was recorded. Every
fork PR with a sizeable API change then got "gate evaluation did not
complete", which the sweep deliberately ignores, so an owner's approval
could not turn it green by either path. The same-repo step already
switches errexit off before the call.

Assisted-by: LLM
Signed-off-by: Myasnikov Daniil <myasnikovdaniil2001@gmail.com>

.github/workflows/api-review-gate-fork.yaml

@@ -215,6 +215,9 @@ jobs:
         id: detect
         run: |
           set -uo pipefail
+          # api-gate exits 2 for a sizeable change; the runner's default `bash -e`
+          # would end the step there, before the code is read.
+          set +e
           "${RUNNER_TEMP}/api-gate" \
             --base "${RUNNER_TEMP}/base" \
             --head "${RUNNER_TEMP}/head" \