## Summary

In this PR I started adding integration tests for the case action. This
process revealed a couple of bugs which I fixed. Specifically this PR:
- Handles decorated errors thrown by the SO client
- Skip executing if there are no alerts
- Pass an unsecured (security is disabled) version of the SO client
- Create one attachment with all alerts instead of one attachment per
alert
- Registers the required kibana privileges the case action needs to run
- Add integration tests

Blocked by: #178307
Flaky test runner:
https://buildkite.com/elastic/kibana-flaky-test-suite-runner/builds/5488


### Checklist

Delete any items that are not applicable to this PR.

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
- [x] [Flaky Test
Runner](https://ci-stats.kibana.dev/trigger_flaky_test_runner/1) was
used on any tests changed

### For maintainers

- [x] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

## Summary

Depends on: #166267,
#170326,
#169484,
#173740,
#173763,
#178068,
#178307,
#178600,
#180437

PRs:
- #168370
- #169229
- #171754
- #172709
- #173012
- #175107
- #175452
- #175505
- #177033
- #178277
- #177139
- #179796

Fixes: #153837

## Testing

Run Kibana with `--run-examples` if you want to use the "Always firing"
rule.

Create a rule with a case action in observability and the stack. The
security solution is not supported. You should not be able to assign a
case action in a security solution rule.

1. Test the "Reopen closed cases" configuration.
2. Test the "Grouping by" configuration. Only one field is allowed. Not
all fields are persisted in alerts. If you select a field not part of
the alert the case action will create a case where the grouping value is
set to `unknow`.
3. Test the "Time window" feature. You can comment out the validation to
test for shorter times.
4. Verify that the case action is experimental.
5. Verify that based on the rule type the case is created in the correct
solution.
6. Verify that you cannot create a rule with the case action on the
basic license.
7. Verify that the execution of the case action fails if you do not have
permission for cases. Pending work on the system actions framework level
to not allow users to create rules with system actions where they do not
have permission.
8. Stress test the case action by creating multiple rules.

### Checklist

Delete any items that are not applicable to this PR.

- [x]
[Documentation](https://www.elastic.co/guide/en/kibana/master/development-documentation.html)
was added for features that require explanation or tutorials
- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

### For maintainers

- [x] This was checked for breaking API changes and was [labeled
appropriately](https://www.elastic.co/guide/en/kibana/master/contributing.html#kibana-release-notes-process)

## Release notes

Automatically create cases when an alert is triggered.

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>
Co-authored-by: adcoelho <antonio.coelho@elastic.co>
Co-authored-by: Janki Salvi <117571355+js-jankisalvi@users.noreply.github.com>