XWIKI-22492: Livedata filter options are misread (#3700)

* Added a bit of semantics on the options
* Added a live update region for the state of the `active` option.
* Fixed when navigating with arrows and validating with Enter.

xwiki-platform-core/xwiki-platform-web/xwiki-platform-web-war/src/main/webapp/resources/uicomponents/suggest/xwiki.selectize.js

@@ -31,7 +31,7 @@ define('xwiki-selectize', [
   'xwiki-events-bridge'
 ], function($, Selectize, l10n) {
   var optionTemplate = [
-    '<div class="xwiki-selectize-option" data-value="">',
+    '<div class="xwiki-selectize-option" role="option" aria-selected="false" data-value="">',
       '<span class="xwiki-selectize-option-icon"></span>',
       '<span class="xwiki-selectize-option-label"></span>',
     '</div>'
@@ -203,6 +203,25 @@ define('xwiki-selectize', [
         });
       }
     }
+    let oldOnOptionSelect = this.selectize.onOptionSelect;
+    this.selectize.onOptionSelect = function(...args) {
+      const result = oldOnOptionSelect.apply(this, args);
+      // clear aria-selected state on all previously selected elements first
+      this.get$('dropdown').find('.option').attr('aria-selected','false');
+      // then set the aria-selected state of the newly selected element.
+      this.get$('dropdown').find('.selected').attr('aria-selected','true');
+      return result;
+    }
+    let oldSetActiveOption = this.selectize.setActiveOption;
+    this.selectize.setActiveOption = function(option, ...args) {
+      this.liveRegion?.text($(option).text());
+      return oldSetActiveOption.call(this, option, ...args);
+    }
+    // Create a live region to store the value of the currently active option.
+    this.selectize.liveRegion = $('<span>');
+    this.selectize.liveRegion.attr('aria-live', 'assertive');
+    this.selectize.liveRegion.addClass('sr-only');
+    this.selectize.get$('input').after(this.selectize.liveRegion);
     setDropDownAlignment(this.selectize);
     if (this.selectize.settings.takeInputWidth) {
       this.selectize.get$('control').width($(this).data('initialWidth'));