Improve npmplus credential retrieval and messaging (#7532)

* Improve npmplus credential retrieval and messaging

Enhanced the install script to attempt live log monitoring for credentials if not found initially, and updated the info message in npmplus.json to guide users to check docker logs if the credentials file is missing.

* Update npmplus.json

* Change updateable status to true in npmplus.json

frontend/public/json/npmplus.json

@@ -6,7 +6,7 @@
   ],
   "date_created": "2025-03-13",
   "type": "ct",
-  "updateable": false,
+  "updateable": true,
   "privileged": false,
   "interface_port": 81,
   "documentation": "https://github.com/ZoeyVid/NPMplus/blob/develop/README.md",
@@ -39,7 +39,7 @@
     }
   ],
   "default_credentials": {
-    "username": "root",
+    "username": "admin@example.org",
     "password": null
   },
   "notes": [
@@ -52,7 +52,7 @@
       "type": "info"
     },
     {
-      "text": "Application credentials: `cat /opt/.npm_pwd`",
+      "text": "Application credentials: `cat /opt/.npm_pwd` - if file not exist in LXC check docker logs for password with `docker logs npmplus`",
       "type": "info"
     }
   ]