[Docs Site] Add privacy group to Key Transparency and Privacy Gateway (cloudflare#19420)

Author: KianNH

src/content/products/key-transparency.yaml

@@ -4,6 +4,7 @@ product:
   title: Key Transparency Auditor
   url: /key-transparency/
   group: Application security
+  additional_groups: [Privacy]
 
 meta:
   title: Key Transparency Auditor

src/content/products/privacy-gateway.yml

@@ -5,6 +5,7 @@ product:
   title: Privacy Gateway
   url: /privacy-gateway/
   group: Developer platform
+  additional_groups: [Privacy]
 
 meta:
   title: Cloudflare Privacy Gateway