fix(sheets): use foundry.utils.duplicate instead of global duplicate

Foundry V11+ no longer exposes 'duplicate' as a global function.
It must be accessed via foundry.utils.duplicate.

Fixed in:
- actor-sheet.mjs:140
- creature-sheet.mjs:148

This resolves the ReferenceError: duplicate is not defined error
when creating items on actor sheets.

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

module/sheets/actor-sheet.mjs

@@ -137,7 +137,7 @@ export class VermineActorSheet extends ActorSheet {
     // Get the type of item to create.
     const type = header.dataset.type;
     // Grab any data associated with this control.
-    const data = duplicate(header.dataset);
+    const data = foundry.utils.duplicate(header.dataset);
     // Initialize a default name.
     // const name = `New ${type.capitalize()}`;
     const name = game.i18n.localize('ITEMS.new_' + type);