Fixes ISSUE-43849: Executes change on ok when no item selected in multiselector
On multiselector values change, after pressing Ok button, also refresh(handleItemChange) if no elements have been selected, so parameters depending on "selected" elements in multiselector get refreshed.
Also execute onChanges when X icon is clicked for removing an element selected from multiselector outside of the popup window.
Note: It also contains the changes from this MR, as those are related: !66 (merged)