Obtaining currently selected item in lists is not convenient

[alexbudarov]

To get currently selected item in browser screens (table, cards) I should write the following:

    let selectedEntityId = entityListState.selectedEntityId;
    const selectedEntity = items?.find(i => i.id === selectedEntityId);

Problems:

1. Too much code, e.g. when comparing to Vaadin screens (Entity entity = table.getSingleSelected())
2. It's not obvious that selected entity should be taken from items of useEntityList hook. Before found items of , I tried to use entityList and listQueryResult {data}

It would be nice to provide shorter API.

Example of usage:

  function isDeactivateButtonDisabled() {
    let selectedEntityId = entityListState.selectedEntityId;
    const user = items?.find(i => i.id === selectedEntityId);

    let currentUserName = mainStore.userName
    return user == null || !user.active|| user.username === currentUserName
  }

//...
    <Button
        htmlType="button"
        style={{ margin: "0 12px 12px 0" }}
        disabled={isDeactivateButtonDisabled()}
        onClick={handleDeactivateBtnClick}
        key="deactivate"
        type="default"
    >
      <FormattedMessage id="users.deactivate"/>
    </Button>