[Fleet] fix setup error during test

[juliaElastic]

Summary

Fixing flaky tests caused by error in fleet setup after stop is invoked
#118626
#120840

The culprit was a missing await of a promise inside setup.
I could simulate this locally by adding a mockFunction in putComponentTemplate to return a Promise.reject:

const mockFunction = () => Promise.reject(new EsErrors.NoLivingConnectionsError());
function putComponentTemplate(...) {
...
  return {
    clusterPromise: retryTransientEsErrors(
      () => mockFunction(),
      { logger }
    ),
    name,
  };
}

In kibana logs verified that server doesn't crash on this error like before, and Fleet setup failed is logged.

[2021-12-09T16:02:20.524+01:00][WARN ][plugins.fleet] Fleet setup failed
[2021-12-09T16:02:20.524+01:00][WARN ][plugins.fleet] NoLivingConnectionsError: Given the configuration, the ConnectionPool was not able to find a usable Connection for this request.
    at mockFunction (/Users/juliabardi/kibana/kibana/x-pack/plugins/fleet/server/services/epm/elasticsearch/template/install.ts:207:43)
    at esCall (/Users/juliabardi/kibana/kibana/x-pack/plugins/fleet/server/services/epm/elasticsearch/template/install.ts:220:13)
    at retryTransientEsErrors (/Users/juliabardi/kibana/kibana/x-pack/plugins/fleet/server/services/epm/elasticsearch/retry.ts:35:18)
    at retryTransientEsErrors (/Users/juliabardi/kibana/kibana/x-pack/plugins/fleet/server/services/epm/elasticsearch/retry.ts:48:14)
    at ensureDefaultComponentTemplate (/Users/juliabardi/kibana/kibana/x-pack/plugins/fleet/server/services/epm/elasticsearch/template/install.ts:342:5)
    at async Promise.all (index 0)
    at ensureFleetGlobalEsAssets (/Users/juliabardi/kibana/kibana/x-pack/plugins/fleet/server/services/setup.ts:141:27)
    at createSetupSideEffects (/Users/juliabardi/kibana/kibana/x-pack/plugins/fleet/server/services/setup.ts:76:5)
    at awaitIfPending (/Users/juliabardi/kibana/kibana/x-pack/plugins/fleet/server/services/setup_utils.ts:30:20)
    at /Users/juliabardi/kibana/kibana/x-pack/plugins/fleet/server/plugin.ts:381:9
[2021-12-09T16:02:20.532+01:00][INFO ][plugins.securitySolution] Dependent plugin setup complete - Starting ManifestTask

[elasticmachine]

Pinging @elastic/fleet (Team:Fleet)

[juliaElastic]

putComponentTemplate is not returning a promise, but an object containing clusterPromise

[nchaulet]

Good catch 🚀

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 6e2e5ab
• Storybooks Preview

Metrics [docs]

✅ unchanged

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

cc @juliaElastic

[afharo]

LGTM! Nice catch!

[kibanamachine]

💚 Backport successful

Status	Branch	Result
✅	8.0

This backport PR will be merged automatically after passing CI.