use methods from the foundry.utils namespaces instead of their global counterparts

src/module/actor/actor.ts

@@ -113,7 +113,7 @@ export class DS4Actor extends Actor {
         }
 
         // Expand the set of final overrides
-        this.overrides = expandObject({ ...flattenObject(this.overrides), ...overrides });
+        this.overrides = foundry.utils.expandObject({ ...foundry.utils.flattenObject(this.overrides), ...overrides });
     }
 
     protected getOriginatingItemOfActiveEffect(effect: ActiveEffect): DS4Item | undefined {
@@ -284,7 +284,7 @@ export class DS4Actor extends Actor {
         isDelta = false,
         isBar = true,
     ): Promise<this | undefined> {
-        const current = getProperty(this.data.data, attribute);
+        const current = foundry.utils.getProperty(this.data.data, attribute);
 
         // Determine the updates to make to the actor data
         let updates: Record<string, number>;

src/module/actor/sheets/actor-sheet.ts

@@ -169,7 +169,7 @@ export class DS4ActorSheet extends ActorSheet<ActorSheet.Options, DS4ActorSheetD
 
         // Set new value
         const newValue = this.getValue(el);
-        setProperty(itemObject, property, newValue);
+        foundry.utils.setProperty(itemObject, property, newValue);
         this.actor.updateEmbeddedDocuments("Item", [{ ...itemObject }]); // TODO: Improve in upstream
     }
 

src/module/rolls/roll.ts

@@ -13,7 +13,7 @@ export class DS4Roll<D extends Record<string, unknown> = Record<string, unknown>
      * @override
      */
     async render(chatOptions: Parameters<Roll["render"]>[0] = {}): Promise<string> {
-        chatOptions = mergeObject(
+        chatOptions = foundry.utils.mergeObject(
             {
                 user: game.user?.id,
                 flavor: null,