Unset companies and owners (#1185)

* unselect users and companies

* Icon now works with theme

---------

Co-authored-by: vboxuser <vboxuser@Ubu.myguest.virtualbox.org>
Co-authored-by: Charles Bochet <charlesBochet@users.noreply.github.com>

front/src/modules/ui/table/hooks/useUpdateEntityField.ts

@@ -91,8 +91,7 @@ export function useUpdateEntityField() {
       const newSelectedEntity = newFieldValueUnknown;
 
       const fieldName = viewField.metadata.fieldName;
-
-      if (!newSelectedEntity) {
+      if (!newSelectedEntity || newSelectedEntity.id === '') {
         updateEntity({
           variables: {
             where: { id: currentEntityId },