test(server): inventory the public server identity route

The authorization matrix fails for any live route that is neither inventoried nor in its frozen
gap baseline, and GET /server-identity arrived without an entry. Record it as public with no
permission or library access, which is exactly what the route serves.

server/test/e2e/authorization-matrix/route-inventory/manifest.json

@@ -1,7 +1,7 @@
 {
-  "totalRoutes": 648,
+  "totalRoutes": 649,
   "byPermission": {
-    "(none)": 280,
+    "(none)": 281,
     "Permission.ManageMetadataConfig": 38,
     "Permission.EmailSend": 34,
     "Permission.LibraryEditMetadata": 35,

server/test/e2e/authorization-matrix/route-inventory/routes-10.json

@@ -970,5 +970,17 @@
     "isPublic": false,
     "allowDefault": false,
     "useGuards": []
+  },
+  {
+    "file": "server/src/modules/server-identity/server-identity.controller.ts",
+    "className": "ServerIdentityController",
+    "methodName": "getIdentity",
+    "httpMethod": "GET",
+    "path": "/server-identity",
+    "permissions": [],
+    "libraryAccess": [],
+    "isPublic": true,
+    "allowDefault": false,
+    "useGuards": []
   }
 ]