[8.11] [DOCS] Slack api allowed channels (#169706) (#170572)

# Backport

This will backport the following commits from `main` to `8.11`:
- [[DOCS] Slack api allowed channels
(#169706)](#169706)

<!--- Backport version: 8.9.8 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

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Cawley","email":"[email protected]"},"sourceCommit":{"committedDate":"2023-11-03T18:37:56Z","message":"[DOCS]
Slack api allowed channels
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Slack api allowed channels
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Slack api allowed channels
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BACKPORT-->

docs/management/connectors/action-types/slack.asciidoc

@@ -21,35 +21,31 @@ You can choose to use a webhook URL that's specific to a single channel. For exa
 image::management/connectors/images/slack-webhook-connector.png[Slack connector]
 // NOTE: This is an autogenerated screenshot. Do not edit it directly.
 
-Alternatively, you can create a connector that supports multiple channels. For example:
+Alternatively, you can create a connector that supports multiple channels.
+For example:
 
 [role="screenshot"]
 image::management/connectors/images/slack-api-connector.png[Slack API connector]
 // NOTE: This is an autogenerated screenshot. Do not edit it directly.
 
-If you use the latter method, you choose your channel when you create a rule action.
-Thus a connector can be used in multiple rules and actions to communicate with different channels.
+If you use the latter method, you must provide a valid list of Slack channel IDs.
+When you create a rule, each action can communicate with one of these channels.
 
 For Slack setup details, go to <<configuring-slack>>.
 
 [float]
 [[slack-action-configuration]]
 === Test connectors
 
-You can test connectors with the <<execute-connector-api,run connector API>> or
-as you're creating or editing the connector in {kib}. For example:
+You can test connectors as you're creating or editing the connector in {kib}.
+For example: 
 
 [role="screenshot"]
-image::management/connectors/images/slack-api-params.png[Slack API connector test]
+image::management/connectors/images/slack-webhook-params.png[Slack webhook connector test]
 // NOTE: This is an autogenerated screenshot. Do not edit it directly.
 
-Slack actions have the following properties:
-
-Channels::
-One or more channels that your Slack app has access to.
-This option is available only in the web API type of connector.
-
-Message:: The Slack message text, which cannot contain Markdown, images, or other advanced formatting.
+Slack connector actions have message text, which cannot contain Markdown, images, or other advanced formatting.
+For the web API type of connector, you must also choose one of the channel IDs.
 
 [float]
 [[slack-connector-networking-configuration]]
@@ -83,3 +79,4 @@ Before you can create a Slack connector, you must configure your account and obt
 . Copy the `Bot User OAuth Token` so you can paste it into your Slack connector form.
 . If you need to send messages to a private channel, you need to write `/invite @App_name` in it.
   Putting "@" triggers Slack to start auto-suggesting, which is why it then becomes easy to find your app name in the list.
+. To find a channel ID (for example, `C123ABC456`), view the channel details.

x-pack/test/screenshot_creation/apps/response_ops_docs/stack_connectors/slack_connector.ts

@@ -28,11 +28,7 @@ export default function ({ getService, getPageObjects }: FtrProviderContext) {
       await testSubjects.setValue('nameInput', 'Slack api test connector');
       await testSubjects.setValue('secrets.token-input', 'xoxb-XXXX-XXXX-XXXX');
       await commonScreenshots.takeScreenshot('slack-api-connector', screenshotDirectories);
-      await testSubjects.click('create-connector-flyout-save-test-btn');
-      await testSubjects.click('toastCloseButton');
-      await pageObjects.common.closeToast();
-      await commonScreenshots.takeScreenshot('slack-api-params', screenshotDirectories);
-      await testSubjects.click('euiFlyoutCloseButton');
+      await testSubjects.click('create-connector-flyout-back-btn');
     });
 
     it('slack webhook connector screenshots', async () => {