[16.0][web_responsive] refactor: Update web_responsive.scss

- set z-index for .o_searchview_autocomplete element.

web_responsive/static/src/legacy/scss/web_responsive.scss

@@ -393,3 +393,7 @@ body:not(.o_statusbar_buttons) {
         background-color: lighten($o-brand-primary, 40%);
     }
 }
+
+.o_searchview_autocomplete {
+    z-index: 999;
+}