Add(config) create disable_form_content_interpolation option for ignoring $UserDefinedForm in $this->Content

_config/config.yml

@@ -0,0 +1,5 @@
+---
+Name: userformsconfig
+---
+SilverStripe\UserForms\Control\UserDefinedFormController:
+  disable_form_content_interpolation: false

code/Control/UserDefinedFormController.php

@@ -108,6 +108,9 @@ class UserDefinedFormController extends PageController
      */
     public function index(HTTPRequest $request = null)
     {
+        if ($this->config()->disable_form_content_interpolation) {
+            return [];
+        }
         if ($this->Content && $form = $this->Form()) {
             $hasLocation = stristr($this->Content, '$UserDefinedForm');
             if ($hasLocation) {

tests/Control/UserDefinedFormControllerTest.php

@@ -255,7 +255,7 @@ class UserDefinedFormControllerTest extends FunctionalTest
 
         $controller = new UserDefinedFormController($form);
 
-        // check to see if $Form is replaced to inside the content
+        // check to see if $Form is placed in the template
         $index = new ArrayData($controller->index());
         $parser = new CSSContentParser($index->renderWith(__CLASS__));
 
@@ -274,6 +274,22 @@ class UserDefinedFormControllerTest extends FunctionalTest
 
         $this->checkTemplateIsCorrect($parser, $form);
     }
+
+    public function testRenderingIntoTemplateWithDisabledInterpolation()
+    {
+        $form = $this->setupFormFrontend();
+
+        $controller = new UserDefinedFormController($form);
+        $controller->config()->set('disable_form_content_interpolation', true);
+        // check to see if $Form is replaced to inside the content
+        $index = new ArrayData($controller->index());
+        $html = $index->renderWith(__CLASS__);
+        $parser = new CSSContentParser($html);
+
+        $this->assertContains('$UserDefinedForm', $html);
+
+        $this->checkTemplateIsCorrect($parser, $form);
+    }
     /**
      * Publish a form for use on the frontend
      *