[7.x][Security Solution] Rename test spec file (#88842)

[pzl]

Summary

backport of #88842

[kibanamachine]

💛 Build succeeded, but was flaky

• continuous-integration/kibana-ci/pull-request
• Commit: 9b1727b
• Flaky suites:
  • xpack-securitySolutionCypress

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Test Failures

Creates a timeline.Timelines Creates a timeline

Link to Jenkins

Stack Trace

Failed Tests Reporter:
  - Test has failed 19 times on tracked branches: https://github.com/elastic/kibana/issues/79389

AssertionError: Timed out retrying after 60000ms: Expected to find element: `[data-test-subj="description"]`, but never found it.
    at Context.eval (http://localhost:6111/__cypress/tests?p=cypress/integration/timelines/creation.spec.ts:15055:16)

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Metrics [docs]

✅ unchanged

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream