Use 127.0.0.1 when spinning up local loopback server (#7268)

1. Security: 127.0.0.1 binds the server to the local machine only,
making it inaccessible from external networks. 0.0.0.0 binds the server
to all available network interfaces, potentially exposing it to external
access.
2. Performance: Binding to 127.0.0.1 can be more efficient as it
restricts traffic to the local machine, avoiding unnecessary network
overhead.
3. Simplicity: Using 127.0.0.1 ensures that only local applications can
connect, simplifying debugging and reducing the risk of unintended
access.

change/@azure-msal-node-234bf880-8502-4a8e-8755-b58175525b0c.json

@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "Use '127.0.0.1' for the host when spinning up local loopback server",
+  "packageName": "@azure/msal-node",
+  "email": "[email protected]",
+  "dependentChangeType": "patch"
+}

lib/msal-node/src/network/LoopbackClient.ts

@@ -74,7 +74,7 @@ export class LoopbackClient implements ILoopbackClient {
                         resolve(authCodeResponse);
                     }
                 );
-                this.server.listen(0); // Listen on any available port
+                this.server.listen(0, '127.0.0.1'); // Listen on any available port
             }
         );
     }