Add Confidentiality Badge to Test Case Sticky Header

What does this MR do and why?

Relates to #425442 (closed)

As part of &11229 (closed), we have added support for creating and editing confidential test cases in the UI.

While test cases will be migrated to the work items framework mid-next year, this is an interim solution to help enable the Quality team to manage test cases within a single source of truth for ongoing confidential projects.

This MR adds the confidentiality badge to issuable_title.vue, which is used by the sticky header when viewing a test case. This sticky header is only visible when the regular header disappears on scrolling downwards. This MR also adds a workspaceType prop to issuable_body.vue, so that it can be passed to issuable_title.vue to display the correct tooltip text for the confidentiality badge.

Please note: issuable_title.vue is also used when viewing integrated issues from Jira and ZenTao (now deprecated), as well as the old view for requirements through /-/requirements_management/requirements (not work items). However, there should be no user-facing changes to Jira issues or requirements and the confidentiality badge should still not display (same as previous behavior). This is because Jira issues do not support confidentiality, and the projectRequirementsEE query when viewing a project's requirements list does not return the confidential attribute anyway.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Screen_Recording_2023-10-30_at_6.48.42_AM

Confidential Test Case

Before	After

Non-Confidential Test Case

Before	After
	Same as before

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

Test cases

1. Ensure your local GDK has an Ultimate license applied
2. Create a new group and project
3. Visit the project, and go to Build > Test cases
4. Create a new confidential test case with a long description
5. While viewing the test case, scroll down until the sticky header appears. The confidentiality badge should now be displayed on this header.

Regression Testing Jira issues and Requirements

Jira Issues

1. Follow the steps outlined in Jira issue integration to integrate a Jira Cloud account with a project on your local GDK. You will need to either have an existing Jira Cloud account or create a new one, and have issues created in Jira.
2. Once the integration is complete, go to your project and go to Plan > Jira issues on the left sidebar
3. Click on a Jira issue that has a long description
4. When viewing the issue, scroll down until the sticky header is visible
5. Verify the sticky header behaves the same as it does on master

Requirements

1. In a project on your local GDK, go to Plan > Requirements
2. Create a new requirement with a long description
3. Click on the requirement to view it in the right sidebar
4. Scroll down until the sticky header is visible
5. Verify the sticky header behaves the same as it does on master

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.