Add Cache Reserve included storage for Smart Shield Advanced

Author: RebeccaTamachiro

src/content/docs/smart-shield/configuration/cache-reserve/index.mdx

@@ -13,6 +13,8 @@ Available with Smart Shield Advanced.
 
 <Render file="cache-reserve-intro" product="cache" />
 
+Smart Shield Advanced includes 2 TB of storage for Cache Reserve.
+
 ## Asset eligibility
 
 <Render file="cache-reserve-eligibility" product="cache" />