chore: validate symbol upload in ci

[bitsandfoxes]

Part of the integration test project cleanup. We want to make sure symbols are actually getting uploaded.

#skip-changelog

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

Want reviews to match your repository better? Bugbot Learning can learn team-specific rules from PR activity. A team admin can enable Learning in the Cursor dashboard.

^{Reviewed by Cursor Bugbot for commit a0f86df. Configure here.}