feat: update default value for _id fields to use a function for uuid generation

src/models/order.model.ts

@@ -43,7 +43,7 @@ const orderSchema = new Schema<OrderDocument>(
   {
     _id: {
       type: String,
-      default: uuidv4,
+      default: () => uuidv4(),
     },
     userId: {
       type: String,

src/models/product.model.ts

@@ -14,7 +14,7 @@ const productSchema = new Schema<ProductDocument>(
   {
     _id: {
       type: String,
-      default: uuidv4,
+      default: () => uuidv4(),
     },
     name: {
       type: String,

src/models/user.model.ts

@@ -16,7 +16,7 @@ const userSchema = new Schema<UserDocument>(
   {
     _id: {
       type: String,
-      default: uuidv4,
+      default: () => uuidv4(),
     },
     email: {
       type: String,