### Bug report
The MultiSelect TagHelper is rendered as a DropDownList and does not allow multiple selections.
### Reproduction of the problem
https://demos.telerik.com/aspnet-core/multiselect/tag-helper
### Expected/desired behavior
The MultiSelect TagHelper should allow multiple selections.
### Environment
* **Kendo UI version: 2021.3.914
* **jQuery version: 1.12.4
* **Browser: [all]
MultiSelect configured for server-filtering="true" sends an empty request on focusout
<kendo-multiselect for="SelectedOrderIds" style="width:100%"
placeholder="Select addresses..."
datatextfield="ShipName"
datavaluefield="OrderID"
filter="FilterType.Contains"
value="Model.SelectedOrders.Select(x=>x.OrderID)">
<datasource type="DataSourceTagHelperType.Ajax" server-filtering="true">
<transport>
<read url="@Url.Page("Index", "Read")" data="forgeryToken" />
</transport>
<schema data="Data">
<model id="OrderID">
<fields>
<field name="ShipName" type="string"></field>
</fields>
</model>
</schema>
</datasource>
</kendo-multiselect>
An empty request is sent, fetching all data.
A request should not be sent.