Update use-pre-existing-resource.md

updating instructions given the MSI token change, we are now fetching storage tokens on behalf of the user rather than the resource level. So the role requirement has changed from needing storage data blob contributor role on the resource -> needing this role to be assigned to the user.

Author: renaaliu

articles/ai-services/language-service/custom-named-entity-recognition/includes/use-pre-existing-resource.md

@@ -51,7 +51,7 @@ Make sure to enable **Custom text classification / Custom Named Entity Recogniti
 5. Select **Apply**.
 
 >[!Important]
-> * Make sure that your **Language resource** has **storage blob data contributor** role assigned on the storage account you are connecting.
+> * Make sure that the user has storage blob data contributor role assigned for the user making the changes.
 
 ### Add required roles