[9.0 & Serverless] New sub-feature priv for case assignees (elastic#831)

Partially addresses elastic#333.
Makes minor changes to future-proof docs for giving full access to
manage cases and settings.

Previews
- Security docs: [Cases
requirements](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/831/solutions/security/investigate/cases-requirements)
- Kibana docs: [Configure access to
cases](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/831/explore-analyze/alerts-cases/cases/setup-cases)
- Observability docs: [Configure access to cases | Give full access to
manage cases and
settings](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/831/solutions/observability/incident-management/configure-access-to-cases#_give_full_access_to_manage_cases_and_settings)

**Related PRs:**
- Security docs: elastic/security-docs#6641
- Kibana docs: elastic/kibana#215162
- Observability docs:
elastic/observability-docs#4850

Author: nastasha-solomon

explore-analyze/alerts-cases/cases/setup-cases.md

@@ -20,7 +20,7 @@ To access cases in **{{stack-manage-app}}**, you must have the appropriate {{kib
 ::::{note}
 The **{{connectors-feature}}** feature privilege is required to create, add, delete, and modify case connectors and to send updates to external systems.
 
-By default, `All` for the **Cases** feature includes authority to delete cases and comments, edit case settings, add case comments and attachments, and re-open cases unless you customize the sub-feature privileges.
+By default, `All` for the **Cases** feature allows you to have full control over cases, including deleting them, editing case settings, and more. You can customize the sub-feature privileges to limit feature access.
 
 ::::
 

solutions/observability/incident-management/configure-access-to-cases.md

@@ -30,7 +30,7 @@ Below are the minimum required privileges for some common use cases.
     ::::{note}
     Roles without `All` **{{connectors-feature}}** feature privileges cannot create, add, delete, or modify case connectors.
 
-    By default, `All` for the **Cases** feature includes authority to delete cases, delete alerts and comments from cases, edit case settings, add case comments and attachments, and re-open cases unless you customize the sub-feature privileges.
+    By default, `All` for the **Cases** feature allows you to have full control over cases, including deleting them, editing case settings, and more. You can customize the sub-feature privileges to limit feature access.
 
     ::::
 

solutions/security/investigate/cases-requirements.md

@@ -25,7 +25,7 @@ To grant access to cases in a custom role, set the privileges for the **Cases**
 
 | Action | {{kib}} Privileges |
 | --- | --- |
-| Give full access to manage cases and settings | - **All** for the **Cases** feature under **Security**<br> - **All** for the **{{connectors-feature}}** feature under **Management**<br><br>**Note:** Roles without **All** privileges for the **{{connectors-feature}}** feature cannot create, add, delete, or modify case connectors. By default, **All** for the **Cases** feature allows you to delete cases, delete alerts and comments from cases, and edit case settings. You can customize the sub-feature privileges to limit feature access.<br><br><br><br> |
+| Give full access to manage cases and settings | - **All** for the **Cases** feature under **Security**<br> - **All** for the **{{connectors-feature}}** feature under **Management**<br><br>**Note:** Roles without **All** privileges for the **{{connectors-feature}}** feature cannot create, add, delete, or modify case connectors. <br><br> By default, **All** for the **Cases** feature allows you to have full control over cases, including deleting them, editing case settings, and more. <br><br><br><br> |
 | Give assignee access to cases | **All** for the **Cases** feature under **Security**<br><br>**Note:** Before a user can be assigned to a case, they must log into {{kib}} at least once, which creates a user profile. <br><br> |
 | Give view-only access for cases | **Read** for the **Security** feature and **All** for the **Cases** feature<br><br> **Note:** You can customize the sub-feature privileges to allow access to deleting cases, deleting alerts and comments from cases, viewing or editing case settings, adding case comments and attachments, and re-opening cases. <br><br> |
 | Revoke all access to cases | **None** for the **Cases** feature under **Security** |