Views blocks that are disabled should not appear in block UI/layout builder

Problem/Motivation

Disbled block type displays of views appears in block UI/layout builder adding list.

Steps to reproduce

1. Create a standard D11 installation
2. Go to Content view edit page (admin/structure/views/view/content)
3. Add a Block type display to the view and rename it "Test block"
4. In the view edit page disable the block by cliking "Disable Test block" link
5. Save the view
6. Go to Claro's Block layout page (admin/structure/block/list/claro)
7. Click on "Place block" button for any region
8. Our disabled block, "Test block", appears in the list

Proposed resolution

Hide disabled view blocks from the block adding list.

Merge request link

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet