Warnings for a class attribute on a modal in the selection page

1. Add an element to your selection.

2. Open the JS console.

3. Browse to the selection.

4. Get this warning twice per project shown in the selection:

   [Vue warn]: Extraneous non-props attributes (class) were passed to component but could not be automatically inherited because component renders fragment or text root nodes. 
     at <Modal class="classification-modal" modelValue=false onUpdate:modelValue=fn  ... > 
     at <CorpusSelection key=0 corpus-id="[...]" > 
     at <Selection onVnodeUnmounted=fn<onVnodeUnmounted> ref=Ref<Proxy { <target>: {…}, <handler>: {…} }>> 
     at <RouterView> 
     at <App>