pinakes-plugin-api: restrict validate_element to pub(crate)

Signed-off-by: NotAShelf <raf@notashelf.dev>
Change-Id: Ifdffa6f56261bfa8c4e8a345ba8e9c4f6a6a6964

crates/pinakes-plugin-api/src/validation.rs

@@ -134,7 +134,10 @@ impl SchemaValidator {
   }
 
   /// Recursively validate a [`UiElement`] subtree.
-  pub fn validate_element(element: &UiElement, errors: &mut Vec<String>) {
+  pub(crate) fn validate_element(
+    element: &UiElement,
+    errors: &mut Vec<String>,
+  ) {
     match element {
       UiElement::Container { children, .. }
       | UiElement::Grid { children, .. }