search: disable integration test for structural search alerts

Created by: rvantonder

This is confirmed flake. I think it might be a combination of racing/priority for alerts (?). This test specifically is probably also better as a unit test/static test now.

Red in: https://buildkite.com/sourcegraph/sourcegraph/builds/153113#018144cb-c641-4005-b816-c100039fb466

Green in commit after: https://buildkite.com/sourcegraph/sourcegraph/builds/153117

Test plan

Remove flake.