always run using app server also in production mode [capacitor]

**Description:**
After making the build in production, the app runs in external server mode

ionic build --prod && npx cap copy android && npx cap open android

the strange thing is that it initially worked the right way

**My `ionic info`:**

```
Ionic:

Ionic CLI : 5.4.6 (/Users/emanuele/.nvm/versions/node/v11.6.0/lib/node_modules/ionic)
Ionic Framework : @ionic/angular 4.9.1
@angular-devkit/build-angular : 0.801.3
@angular-devkit/schematics : 8.1.3
@angular/cli : 8.1.3
@ionic/angular-toolkit : 2.0.0

Capacitor:

Capacitor CLI : 1.3.0
@capacitor/core : 1.3.0

Cordova:

Cordova CLI : 8.0.0
Cordova Platforms : none
Cordova Plugins : no whitelisted plugins (0 plugins total)

Utility:

cordova-res : 0.6.0 (update available: 0.8.1)
native-run : 0.2.8 (update available: 0.2.9)

System:

NodeJS : v11.6.0 (/Users/emanuele/.nvm/versions/node/v11.6.0/bin/node)
npm : 6.11.3
OS : macOS Mojave
Xcode : Xcode 11.2 Build version 11B52
```