[FIX] Re-added template variables for SearchFormViewHelper

This PR re-introduces the template variables in the SearchFormViewHelper

Cherry-Picked from: 8f60143
Fixes: #4117
Ports: #4118

Classes/ViewHelpers/SearchFormViewHelper.php

@@ -79,7 +79,7 @@ public function initializeArguments(): void
     }
 
     /**
-     * Render search form tag
+     * Renders search form-tag
      *
      * @throws AspectNotFoundException
      * @noinspection PhpMissingReturnTypeInspection
@@ -110,12 +110,32 @@ public function render()
         // @extensionScannerIgnoreLine
         $this->getTemplateVariableContainer()->add('q', $this->getQueryString());
         // @extensionScannerIgnoreLine
+        $this->getTemplateVariableContainer()->add('pageUid', $pageUid);
+        // @extensionScannerIgnoreLine
+        $this->getTemplateVariableContainer()->add(
+            'languageUid',
+            (
+                $this->renderingContext
+                    ->getAttribute(ServerRequestInterface::class)
+                    ->getAttribute('language')
+                    ?->getLanguageId() ?? 0
+            )
+        );
+        // @extensionScannerIgnoreLine
         $this->getTemplateVariableContainer()->add('existingParameters', $this->getExistingSearchParameters());
         // @extensionScannerIgnoreLine
+        // Added addPageAndLanguageId for compatibility
+        $this->getTemplateVariableContainer()->add('addPageAndLanguageId', false);
         $formContent = $this->renderChildren();
         // @extensionScannerIgnoreLine
+        $this->getTemplateVariableContainer()->remove('addPageAndLanguageId');
+        // @extensionScannerIgnoreLine
         $this->getTemplateVariableContainer()->remove('q');
         // @extensionScannerIgnoreLine
+        $this->getTemplateVariableContainer()->remove('pageUid');
+        // @extensionScannerIgnoreLine
+        $this->getTemplateVariableContainer()->remove('languageUid');
+        // @extensionScannerIgnoreLine
         $this->getTemplateVariableContainer()->remove('existingParameters');
 
         $this->tag->setContent($formContent);