docs: fix links to extend workflow guide (#10269)

www/apps/api-reference/markdown/admin.mdx

@@ -832,7 +832,7 @@ If you click on the workflow, you'll view a reference of that workflow, includin
 
 This is useful if you want to extend an API route and pass additional data or perform custom actions.
 
-Refer to [this guide](https://docs.medusajs.com/customization/extend-models/extend-create-product) to find an example of extending an API route.
+Refer to [this guide](https://docs.medusajs.com/learn/customization/extend-models/extend-create-product) to find an example of extending an API route.
 
 <Feedback
   event="survey_api-ref"

www/apps/api-reference/markdown/store.mdx

@@ -831,7 +831,7 @@ If you click on the workflow, you'll view a reference of that workflow, includin
 
 This is useful if you want to extend an API route and pass additional data or perform custom actions.
 
-Refer to [this guide](https://docs.medusajs.com/customization/extend-models/extend-create-product) to find an example of extending an API route.
+Refer to [this guide](https://docs.medusajs.com/learn/customization/extend-models/extend-create-product) to find an example of extending an API route.
 
 <Feedback
   event="survey_api-ref"