Fix misleading artifact storage deletion note (#60553)

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: holly-kassel

content/billing/concepts/product-billing/github-actions.md

@@ -165,7 +165,7 @@ If you use 3 GB of artifact storage for 10 days of March and 12 GB for 21 days o
 At the end of the month, {% data variables.product.github %} rounds your artifact storage to the nearest MB. Therefore, your artifact storage usage for March would be 9.097 GB.
 
 > [!NOTE]
-> {% data variables.product.github %} updates your artifact storage space within a 6 to 12-hour window. If you delete artifacts, the available space will be reflected in your account during the next scheduled update.
+> {% data variables.product.github %} updates your artifact storage usage within 6 to 12 hours. Deleting artifacts frees up space for current storage, but does not reduce your accrued storage usage, which is used to calculate your storage billing for the current billing cycle.
 
 ### Example cache storage cost calculation