ci: update condition for downloading artifact in perf test workflow

.github/workflows/performance_test.yaml

@@ -58,7 +58,7 @@ jobs:
         python-version: '3.11'
     - run: pip install -r requirements.txt
     - uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
-      if: github.event_name == 'workflow_call'
+      if: github.event_name != 'workflow_dispatch'
       with:
         pattern: "emqx-enterprise-ubuntu22.04-amd64-*"
     - name: Download emqx package