Feature: #81656 - Select view helper supports required argument

See forge#81656

Description

The select view helper supports the optional argument required according to this: https://www.w3schools.com/tags/att_select_required.asp

Impact

Set the "required" argument like this:

<f:form.select property="category" required="1" options="{categories}" />
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The rendered html output is this:

<select required="required" name="tx_ext[model][category]">
    <option value="...">...</option>
</select>
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