[Alerting] Handling connectors with missing secrets during rule creation and action execution

[ymao1]

Resolves #94128

Summary

This PR does a few things to handle connectors where isMissingSecrets: true:

1. Removes connectors with isMissingSecrets: true from the list of available connectors during rule creation. This means imported connectors that have not been fixed will not show up in the list of available connectors in the AlertAdd flyout.
2. Extends action validation during rule creation/update to check the isMissingSecrets value for the connector used by each action. This should prevent actions with bad connectors from being added via the rule API.
3. Before action execution, check the isMissingSecrets value for connector used by the action and throws an error if it is true This shows up in the UI like:

To verify

1. Create an ndjson file with the following:

{"attributes":{"actionTypeId":".resilient","config":{"apiUrl":"https://resilient","orgId":"abc"},"isMissingSecrets":true,"name":"resilient connector","secrets":null},"coreMigrationVersion":"8.0.0","id":"b2833c90-a78b-11eb-a1a3-7ba49ae0dd71","migrationVersion":{"action":"7.14.0"},"references":[],"type":"action","updated_at":"2021-04-27T19:06:40.255Z","version":"WzIwLDFd"}
{"attributes":{"actionTypeId":".email","config":{"from":"me@me.com","hasAuth":false,"host":"hello","port":22,"secure":null,"service":null},"isMissingSecrets":true,"name":"email connector","secrets":null},"coreMigrationVersion":"8.0.0","id":"904d4d50-a78b-11eb-a1a3-7ba49ae0dd71","migrationVersion":{"action":"7.14.0"},"references":[],"type":"action","updated_at":"2021-04-27T19:06:55.575Z","version":"WzIxLDFd"}
{"attributes":{"actionTypeId":".slack","config":{},"isMissingSecrets":true,"name":"slack connector","secrets":null},"coreMigrationVersion":"8.0.0","id":"a2bcb160-a78b-11eb-a1a3-7ba49ae0dd71","migrationVersion":{"action":"7.14.0"},"references":[],"type":"action","updated_at":"2021-04-27T19:07:10.203Z","version":"WzIyLDFd"}
{"attributes":{"actionTypeId":".jira","config":{"apiUrl":"https://jira","projectKey":"foo"},"isMissingSecrets":true,"name":"jira connector","secrets":null},"coreMigrationVersion":"8.0.0","id":"ceae6340-a78b-11eb-a1a3-7ba49ae0dd71","migrationVersion":{"action":"7.14.0"},"references":[],"type":"action","updated_at":"2021-04-27T19:07:27.489Z","version":"WzIzLDFd"}
{"exportedCount":4,"missingRefCount":0,"missingReferences":[]}

2. Import this file via the Saved Objects Management UI
3. Create a new rule via the UI. Verify that none of the imported connectors are available to be used
4. Create a rule via the API that has an action that uses one of the imported connectors. Verify that you get a 400 error.

Checklist

Delete any items that are not applicable to this PR.

• Unit or functional tests were updated or added to match the most common scenarios

[elasticmachine]

Pinging @elastic/kibana-alerting-services (Team:Alerting Services)

[YulNaumenko]

Overall changes LGTM! I have only question about the error message.

[kibanamachine]

💚 Build Succeeded

• continuous-integration/kibana-ci/pull-request
• Commit: 2e52cc2
• Storybooks Preview
• Documentation Changes

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
triggersActionsUi	1.5MB	1.5MB	+47.0B

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
triggersActionsUi	106.1KB	106.3KB	+210.0B

History

• 💚 Build #122993 succeeded 47cf26a
• 💚 Build #122974 succeeded 3f4a025

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

cc @ymao1

[kibanamachine]

💚 Backport successful

Status	Branch	Result
✅	7.x

This backport PR will be merged automatically after passing CI.