fix(dropdown): fix html for placeholder

If a placeholder text contained HTML (for example an icon) if was not remembered when reused (for example when the dropdown is cleared)

Author: lubber-de

src/definitions/modules/dropdown.js

@@ -1772,7 +1772,7 @@ $.fn.dropdown = function(parameters) {
             return $module.data(metadata.placeholderText) || '';
           },
           text: function() {
-            return $text.text();
+            return settings.preserveHTML ? $text.html() : $text.text();
           },
           query: function() {
             return String($search.val()).trim();