Flaky E2E: Onboarding - Select "Travel Agencies & Services" category

### Spec file

specs/onboarding/setup__build.ts

### TeamCity ID

9127710

### Logs

```
page.waitForLoadState: Timeout 20000ms exceeded.
at StartSiteFlow.enterVertical (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/packages/calypso-e2e/src/lib/flows/start-site-flow.ts:100:19)
at Object. (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/test/e2e/specs/onboarding/setup__build.ts:42:25)
at Promise.then.completed (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-circus/build/utils.js:391:28)
at callAsyncCircusFn (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-circus/build/utils.js:316:10)
at _callCircusTest (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-circus/build/run.js:218:40)
at _runTest (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-circus/build/run.js:155:3)
at _runTestsForDescribeBlock (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-circus/build/run.js:66:9)
at _runTestsForDescribeBlock (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-circus/build/run.js:60:9)
at _runTestsForDescribeBlock (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-circus/build/run.js:60:9)
at run (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-circus/build/run.js:25:3)
at runAndTransformResultsToJestFormat (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-circus/build/legacy-code-todo-rewrite/jestAdapterInit.js:170:21)
at jestAdapter (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-circus/build/legacy-code-todo-rewrite/jestAdapter.js:82:19)
at runTestInternal (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-runner/build/runTest.js:389:16)
at runTest (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-runner/build/runTest.js:475:34)
at Object.worker (/home/teamcity-2/buildAgent/work/c4a9d5b38c1dacde/node_modules/jest-runner/build/testWorker.js:133:12)
```

Start with specs/onboarding/setup__build.ts and the failure at line 42, then inspect packages/calypso-e2e/src/lib/flows/start-site-flow.ts at line 100. Run the onboarding E2E using TeamCity build 9127710 or an equivalent environment and determine why page.waitForLoadState times out; done means the category flow completes reliably without this timeout.

Written by the indexing model from the issue text.