[FIX] web: remove unneeded overflow-y on modal-body class

Will fix problem where opened dropdown list were hidden behind the modal footer

addons/web/static/src/xml/base.xml

@@ -40,7 +40,7 @@
                     <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
                     <h3 class="modal-title"><t t-raw="title"/></h3>
                 </div>
-                <div class="modal-body" style="overflow-y: auto;">
+                <div class="modal-body">
                 </div>
             </div>
         </div>