4.1.5 🌈

Changes

• [4.1][READY] Fix for mutated attributes @pxpm (#2815)
• [4.1][Tests] Add tests to get attribute in select columns. @pxpm (#2827)
• [4.1.x] do not add route or sidebar content if it already exists @tabacitu (#2830)
• [4.1] Fixed include_all_form_fields option for relationship fields @zunderbolt (#2792)
• [4.1] Fix FetchOperation with custom query @dave-mills (#2818)
• Translated relationship and relationship fetch default placeholder @promatik (#2825)
• fixed widgets are not shown with after_content @onkbear (#2819)
• Fixed details row icon @promatik (#2821)
• Fixed placeholder on relationship fetch field @promatik (#2824)