Fix tag border color Relations (#3034)

- fix tag theme types
- fix color for tag border

packages/twenty-front/src/modules/settings/data-model/object-details/components/SettingsObjectFieldDataType.tsx

@@ -35,7 +35,7 @@ const StyledDataType = styled.div<{ value: FieldMetadataType }>`
   ${({ theme, value }) =>
     value === FieldMetadataType.Relation
       ? css`
-          border-color: ${theme.color.purple20};
+          border-color: ${theme.tag.background.purple};
           color: ${theme.color.purple};
         `
       : ''}