Fix issue with Placeholder when it is undefined the filter-control plugin is not rendering the control

src/extensions/filter-control/bootstrap-table-filter-control.js

@@ -257,7 +257,7 @@
                 if (column.searchable && that.options.filterTemplate[nameControl]) {
                     addedFilterControl = true;
                     isVisible = 'visible';
-                    html.push(that.options.filterTemplate[nameControl](that, column.field, isVisible, column.filterControlPlaceholder));
+                    html.push(that.options.filterTemplate[nameControl](that, column.field, isVisible, column.filterControlPlaceholder ? column.filterControlPlaceholder : ""));
                 }
             }