fix #5488: add ARIA labeling to hide edit menu from screen readers wh…

[guillermo-escire]

References

Fixes #5488

Description

Adds dynamic ARIA labeling to the DSO edit menu so that when a user has no edit permissions, the menu is hidden from screen readers and the role="menubar" attribute is removed, preventing the broken ARIA menu error detected by the WAVE accessibility tool.

Instructions for Reviewers

List of changes in this PR:

• dso-edit-menu.component.html: role="menubar" is now dynamic — only applied when the menu has visible subsections. Added aria-hidden="true" when no subsections are visible.
• dso-edit-menu.component.ts: Added menuVisibleWithSections$ observable that checks real subsections with permissions via getSubSectionsByParentID.
• dso-edit-menu.component.spec.ts: Added tests to verify DOM behavior for both cases.

How to test:

1. Install the WAVE browser extension
2. Navigate to any community or item page without being logged in
3. Run WAVE — the Broken ARIA menu error should no longer appear
4. Log in as an admin and navigate to the same pages — the edit menu (three dots) should still appear and work correctly

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