[Cases] Multiple alerts user action on the UI

[cnasikas]

Summary

This PR shows a user action on the single page of a case when bulk alerts are attached to a case. At the moment users are not able to bulk attach alerts to a case.

Testing

POST /api/cases/<case_id>/comments
{
    // You can add as many alert ids as you want.
    "alertId": [<alert_id>, <alert_id>],
    // Index should have the same length as the alertId array
    "index": [<index>, <index>],
    "rule": { "id": <rule_id>, "name": <rule_name> },
    "type": "alert",
    "owner": "securitySolution"
}

Checklist

Delete any items that are not applicable to this PR.

• Any text added follows EUI's writing guidelines, uses sentence case text and includes i18n support
• Unit or functional tests were updated or added to match the most common scenarios

For maintainers

• This was checked for breaking API changes and was labeled appropriately

[elasticmachine]

Pinging @elastic/response-ops (Team:ResponseOps)

[elasticmachine]

Pinging @elastic/response-ops-cases (Feature:Cases)

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: 9c114b1
• Storybooks Preview
• Webpack Bundle Analyzer

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
cases	283.9KB	285.6KB	+1.7KB

Unknown metric groups

ESLint disabled line counts

id	before	after	diff
cases	76	75	-1

Total ESLint disabled count

id	before	after	diff
cases	92	91	-1

History

• 💔 Build #38923 failed 53ef748
• 💔 Build #38406 failed b7a6a3d2a17718a6e7ed00f3744371ae25131f3c
• 💔 Build #38230 failed 56d9ea43cf6126f7cfe3c3d4bdbe07ad73495c80

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

cc @cnasikas

[academo]

tested it locally and works well.