Add mixed-port to generalConfig in META.js

Introduces the 'mixed-port' property with value 7890 to the generalConfig object and removes the 'external-controller' property. This updates the configuration to support mixed-port usage and cleans up unused settings.

META.js

@@ -154,12 +154,12 @@ function extractFavicon(domain) {
 // General Configuration
 
 const generalConfig = {
+  "mixed-port": 7890,
   "allow-lan": false,
   mode: "rule",
   "log-level": "info",
   ipv6: true,
   "find-process-mode": "strict",
-  "external-controller": "",
   profile: {
     "store-selected": true,
     "store-fake-ip": true,