Could not found cordova.js script tag, Plugin loading may fail

**Description:**

start a new project width ionic-cli , type is cordova, add some usual plugins, run on device, the console show this error

**Steps to Reproduce:**

1. ionic start project --type=angular --cordova
2. ionic cordova plugin add cordova-plugin-inappbrowser cordova-clipboard cordova-plugin-app-version cordova-plugin-camera cordova-plugin-qrscanner
3. ionic cordova platform add android/ios
4. ionic cordova prepare ios/android --prod
5. build app, run on device

**Output:**

console show "Could not found cordova.js script tag, Plugin loading may fail"

**My `ionic info`:**

```
Ionic:

Ionic CLI : 6.11.8 (/Users/zhuxian/.nvm/versions/node/v12.18.3/lib/node_modules/@ionic/cli)
Ionic Framework : @ionic/angular 5.3.2
@angular-devkit/build-angular : 0.1000.8
@angular-devkit/schematics : 10.0.8
@angular/cli : 10.0.8
@ionic/angular-toolkit : 2.3.3

Cordova:

Cordova CLI : 10.0.0
Cordova Platforms : android 9.0.0, ios 6.1.1
Cordova Plugins : cordova-plugin-ionic-keyboard 2.2.0, cordova-plugin-ionic-webview 5.0.0, (and 15 other plugins)

Utility:

cordova-res : 0.15.1
native-run : 1.0.0

System:

Android SDK Tools : 26.1.1 (/Users/zhuxian/Library/Android/sdk)
ios-deploy : 1.10.0
ios-sim : 8.0.2
NodeJS : v12.18.3 (/Users/zhuxian/.nvm/versions/node/v12.18.3/bin/node)
npm : 6.14.8
OS : macOS Catalina
Xcode : Xcode 11.7 Build version 11E801a
```

**Other Information:**

Reproduce the warning with the listed ionic start, plugin, platform, prepare, and device-build commands, using the provided Ionic, Cordova, and Node versions as context. Trace the CLI's Cordova project and plugin-loading workflow; done means the device build no longer reports that the cordova.js script tag is missing.

索引モデルが issue の本文から書いたものです。