DEVDOCS-6697 - Remove code object from Create a Promotion API Spec (#1225)

<!-- Ticket number or summary of work -->
# [DEVDOCS-6697]


## What changed?
<!-- Provide a bulleted list in the present tense -->
* Removed code object from create a promotion API reference as this is
for internal use only and not to be shown publicly.

## Release notes draft
Removed code object from create a promotion API reference as this is for
internal use only and not to be shown publicly.

ping @bigcommerce/dev-docs @bc-terra 


[DEVDOCS-6697]:
https://bigcommercecloud.atlassian.net/browse/DEVDOCS-6697?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

Author: chris-nowicki

reference/promotions.v3.yml

@@ -4,7 +4,7 @@ info:
   version: '1.0'
   description: |
     A *promotion* is composed of a condition that a customer can satisfy, such as increasing their cart value above a certain amount or adding an item to their cart. 
-    
+
     After the customer satisfies the condition, an action takes place, such as a free item being added to the cart or a discount applying itself to the order total.
 
     To learn more about promotions, consult the [Promotions Overview](/docs/store-operations/promotions).
@@ -279,15 +279,15 @@ paths:
           content: {}
         '422':
           $ref: '#/components/responses/BulkDeleteResponse'
-          
+
   '/promotions/{promotion_id}/codegen':
     post:
       tags:
         - Coupon Codes (Bulk)
       summary: Generate Multiple Coupon Codes
       description: |-
         Generate a batch of coupon codes for a particular bulk coupon promotion.
-        
+
         **Note:**
         * batch_size (number of codes generated per request) is limited to 250. If batch_size is not an integer or larger than 250, it will return a 422 error code.
         * The default rate limit for this endpoint is 10 concurrent requests.
@@ -351,7 +351,6 @@ paths:
               schema:
                 $ref: '#/components/schemas/ErrorResponse'
 
-
   '/promotions/codes':
     parameters:
       - $ref: '#/components/parameters/Accept'
@@ -361,7 +360,7 @@ paths:
       summary: Get A Coupon Code
       description: |-
         Get a coupon with a given coupon code.
-        
+
         **Note:**
         The default rate limit for this endpoint is 40 concurrent requests.
       operationId: getCouponCodeByCode
@@ -376,7 +375,7 @@ paths:
       summary: Delete A Coupon Code
       description: |-
         Deletes a coupon with a given coupon code.
-        
+
         **Note:**
         The default rate limit for this endpoint is 40 concurrent requests.
       operationId: deleteCouponCodeByCode
@@ -536,8 +535,6 @@ components:
         - $ref: '#/components/schemas/PromotionBase'
         - type: object
           properties:
-            codes:
-              $ref: '#/components/schemas/CouponCode'
             coupon_overrides_automatic_when_offering_higher_discounts:
               type: boolean
               example: false
@@ -599,9 +596,9 @@ components:
               type: object
               properties:
                 has_multiple_codes:
-                    type: boolean
-                    example: false
-                    default: false
+                  type: boolean
+                  example: false
+                  default: false
             coupon_type:
               type: string
               enum:
@@ -1256,11 +1253,7 @@ components:
     CursorPagination:
       title: Cursor Pagination
       type: object
-      required: [
-        count,
-        per_page,
-        links
-      ]
+      required: [count, per_page, links]
       properties:
         count:
           type: integer
@@ -1390,7 +1383,7 @@ components:
             - CART_PAGE
             - CHECKOUT_PAGE
           items:
-              type: string
+            type: string
       description: |-
         **Notification**
         A notification displayed to the user based on the result of executing a promotion, for example, a "Congratulations! Youʼve received free shipping!" message when the shopper receives free shipping.
@@ -1451,7 +1444,7 @@ components:
               items:
                 minItems: 1
                 type: string
-                example: "0439538491"
+                example: '0439538491'
     CouponCode:
       description: A `CouponCode` object encapsulates attributes of a coupon code.
       type: object
@@ -1816,8 +1809,8 @@ components:
                 title: Errors occurred in bulk delete action.
                 type: 'https://developer.bigcommerce.com/api-docs/getting-started/api-status-codes'
                 errors:
-                  0.constraint: "Failed for id=12. Error: constraint reference error."
-                  2.code: "Failed for id=14. Error: some relating codes are still present."
+                  0.constraint: 'Failed for id=12. Error: constraint reference error.'
+                  2.code: 'Failed for id=14. Error: some relating codes are still present.'
             meta:
               total: 5
               success: 3