VAULT-24439: Make sys/config/ui/custom-messages enterprise paths (#25696)

* remove uiCustomMessagePaths from System backend paths

* adjust documentation

* grammar improvements in docs

* add ENT badge to custom-message api docs page in ToC

vault/logical_system.go

@@ -192,7 +192,6 @@ func NewSystemBackend(core *Core, logger log.Logger, config *logical.BackendConf
 
 	b.Backend.Paths = append(b.Backend.Paths, entPaths(b)...)
 	b.Backend.Paths = append(b.Backend.Paths, b.configPaths()...)
-	b.Backend.Paths = append(b.Backend.Paths, b.uiCustomMessagePaths()...)
 	b.Backend.Paths = append(b.Backend.Paths, b.rekeyPaths()...)
 	b.Backend.Paths = append(b.Backend.Paths, b.sealPaths()...)
 	b.Backend.Paths = append(b.Backend.Paths, b.statusPaths()...)

website/content/api-docs/system/config-ui-custom-messages.mdx

@@ -6,6 +6,8 @@ description: The '/sys/config/ui/custom-messages' endpoint configures the custom
 
 # `/sys/config/ui/custom-messages`
 
+@include 'alerts/enterprise-only.mdx'
+
 The `/sys/config/ui/custom-messages` endpoint is used to list, create, read, update, or delete custom messages.
 
 ## List custom messages

website/content/api-docs/system/internal-ui-authenticated-messages.mdx

@@ -10,6 +10,9 @@ description: >-
 The `/sys/internal/ui/authenticated-messages` endpoint is used by the UI to
 retrieve the active post-login custom messages so that it can display them.
 
+You must install Vault Enterprise 1.16.0 or higher to create custom messages
+that can be retrieved using this endpoint.
+
 When retrieving custom messages, the results will include active messages from
 the current namespace along with custom messages that exist all of the ancestral
 namespaces up to and including the root namespace.

website/content/api-docs/system/internal-ui-unauthenticated-messages.mdx

@@ -10,6 +10,9 @@ description: >-
 The `/sys/internal/ui/unauthenticated-messages` endpoint is used by the UI to
 retrieve the active pre-login custom messages so that it can display them.
 
+You must install Vault Enterprise 1.16.0 or higher to create custom messages
+that can be retrieved using this endpoint.
+
 When retrieving custom messages, the results will include active messages from
 the current namespace along with custom messages that exist all of the ancestral
 namespaces up to and including the root namespace.

website/data/api-docs-nav-data.json

@@ -440,7 +440,12 @@
       },
       {
         "title": "<code>/sys/config/ui/custom-messages</code>",
-        "path": "system/config-ui-custom-messages"
+        "path": "system/config-ui-custom-messages",
+        "badge": {
+          "text": "ENT",
+          "type": "outlined",
+          "color": "neutral"
+        }
       },
       {
         "title": "<code>/sys/config/ui/headers</code>",