Fix discover search CCS cancel functional test

[lukasolson]

Summary

Fixes #246775.

In looking at the failures, it looks like we don't get the partial results indicators because the search request completes before we hit the cancel button.

This PR increases the delay so we should realistically never cancel before the search request is complete.

[elasticmachine]

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[kibanamachine]

Flaky Test Runner Stats

🟠 Some tests failed. - kibana-flaky-test-suite-runner#10314

[❌] src/platform/test/functional/config.ccs.ts: 41/50 tests passed.

see run history

[elasticmachine]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: 0477de3

Failed CI Steps

• FTR Configs #29

Test Failures

• [job] [logs] FTR Configs #29 / Endpoint plugin @ess @serverless @skipInServerlessMKI Endpoint artifacts (via lists plugin): Trusted Applications "before all" hook in "@ess @serverless @skipInServerlessMKI Endpoint artifacts (via lists plugin): Trusted Applications"

Metrics [docs]

✅ unchanged