Update Set-CsExternalAccessPolicy.md

This is an update to add a note that FederatedBilateralChats is public preview and also to correct the default value, which is False, not True

Author: andcicedea

teams/teams-ps/teams/Set-CsExternalAccessPolicy.md

@@ -430,6 +430,9 @@ Accept wildcard characters: False
 ```
 
 ### -FederatedBilateralChats
+> [!NOTE]
+> Please note that this parameter is in Private Preview.
+
 This setting enables bi-lateral chats for the users included in the messaging policy.
 
 ```yaml
@@ -439,7 +442,7 @@ Aliases:
 
 Required: False
 Position: Named
-Default value: True
+Default value: False
 Accept pipeline input: False
 Accept wildcard characters: False
 ```