Item-/option-sets are not supported in Macro descriptor

[alansemenov]

Having an item- or option-set in macro descriptor results in console errors and nothing is rendered on the Configuration tab:

Sample descriptor:

<macro>
  <display-name>My macro</display-name>
  <description>Macro test</description>
  <form>
    <input type="TextLine" name="field_name_1">
      <label>field_name_1</label>
      <occurrences minimum="0" maximum="0"/>
    </input>
    <item-set name="item-set">
      <label>Item Set</label>
      <occurrences maximum="0" minimum="0"/>
      <items>
        <input type="TextLine" name="item-set_field_name_1">
          <label>item-set_field_name_1</label>
          <occurrences minimum="0" maximum="0"/>
        </input>
      </items>
    </item-set>
  </form>
</macro>

[alansemenov]

We decided it will not be supported (https://github.com/enonic/xp/issues/8651), but we should handle the error in the frontend.