Add note to 7.16 release notes about requirement for unique integration policy names (#1510) (#1512)

(cherry picked from commit a3ff1b1)

Co-authored-by: DeDe Morton <[email protected]>

Author: mergify[bot]

docs/en/ingest-management/release-notes/release-notes-7.16.asciidoc

@@ -57,6 +57,28 @@ Fleet::
 * Report `installing` status while package install is in progress {kib-pull}111875[#111875]
 
 
+[[known-issue-unique-names]]
+.Integration policy names must be globally unique
+[%collapsible]
+====
+
+*Details*
+
+Starting in 7.16.0, integration policy names must be globally unique.
+
+*Impact*
+
+If you are upgrading from a previous version and have integrations with
+duplicate names, you'll encounter an error when you attempt to upgrade the
+integration: "There is already a package with the same name."
+
+*Workaround*
+
+You must modify all integration policy names to be unique before trying to
+upgrade integrations.
+
+====
+
 // end 7.16.0 relnotes
 
 // ---------------------