3.0: [UI] Multi select doesn't respect disabled checkboxes

## To Reproduce
While choosing relation entries in any piece or page, all the `draft` records will have their checkboxes disabled. Clicking on the Select all (the checkbox at the top of the list) will select the draft records anyway.

## Expected behavior
The multi select component should respect the disabled state of the list, no draft (or because of any other reasons disabled checkboxes) should be checked.

Start by reproducing the issue while choosing relation entries in a piece or page, with draft records disabled. Trace the multi-select component's Select all behavior and verify that disabled checkboxes remain unchecked; done when no disabled record is selected, including records disabled for other reasons.

Written by the indexing model from the issue text.