test: check for uploaded file to be private

cypress/integration/control_markdown_editor.js

@@ -16,7 +16,7 @@ context("Control Markdown Editor", () => {
 		cy.click_modal_primary_button("Upload");
 		cy.get_field("main_section_md", "Markdown Editor").should(
 			"contain",
-			"![](/files/sample_image"
+			"![](/private/files/sample_image"
 		);
 	});
 });