Support toggling dataset element uniqueness

Based on !1659 (merged)

Closes #1385 (closed)

requested review from @babadie

assigned to @vrigal

changed the description

requested review from @erouchet and removed review request for @babadie

changed milestone to %Arkindex 1.6.0

added 18 commits

• f94f13f1...d700f94d - 2 commits from branch master
• d700f94d...fb00908d - 6 earlier commits
• 3321cec6 - remove field-label css
• e94f2572 - Add watchers to reset the set name fields when the parent modal is closed
• fc1b1d47 - Fix element dataset navigation
• 5f44e8fa - fix adding elements to a dataset set from selection
• f187798d - apply review
• 204ee9e7 - Update API
• ca19efb0 - Display and edit dataset unique_elements attribute
• b5d6c450 - Make error from selection more explicit
• 9b7ffd24 - Fix typing
• a367e1eb - Show field error for unique_elements

Compare with previous version

added 7 commits

• a367e1eb...1cf56b72 - 2 commits from branch master
• 2be26788 - Update API
• d7931fd4 - Display and edit dataset unique_elements attribute
• 6f398e01 - Make error from selection more explicit
• f462c55b - Fix typing
• b3493595 - Show field error for unique_elements

Compare with previous version

enabled an automatic merge when the pipeline for b3493595 succeeds

merged