base-href still not recognized / applied properly

**Description:**
When `--base-href` is passed to the build command (i.e. for browser target), it doesn't result in index.html file with proper `` tag

**Steps to Reproduce:**
`ionic cordova build browser -- --base-href=/ionic/`

**Output:**
Resulting `index.html` contents:

```

```

Expected:
```

```

as when building regular Angular app.

**My `ionic info`:**
```
Ionic:

Ionic CLI : 6.11.9 (/opt/local/lib/node_modules/@ionic/cli)
Ionic Framework : @ionic/angular 5.3.3
@angular-devkit/build-angular : 0.1001.0
@angular-devkit/schematics : 10.1.0
@angular/cli : 10.1.0
@ionic/angular-toolkit : 2.3.3

Cordova:

Cordova CLI : 10.0.0
Cordova Platforms : 6.0.0, android 9.0.0, browser, ios 6.1.1
Cordova Plugins : cordova-plugin-ionic-keyboard 2.2.0, cordova-plugin-ionic-webview 5.0.0, (and 12 other plugins)

Utility:

cordova-res : 0.15.1
native-run : 1.1.0

System:

Android SDK Tools : 26.1.1 (/Users/rattkin/Library/Android/sdk)
ios-deploy : 1.10.0
ios-sim : 8.0.2
NodeJS : v12.18.3 (/opt/local/bin/node)
npm : 6.14.8
OS : macOS Catalina
Xcode : Xcode 12.0.1 Build version 12A7300
```

**Other Information:**
It seems that *it is* passed down the line, but just not respected. That command above results first in
`ng run gpa-mobile:ionic-cordova-build --platform=browser`
and later in
`cordova build browser --base-href=/ionic/`

But the index.html is not changed.

Trace the build flow from `ionic cordova build browser -- --base-href=/ionic/` through `ng run gpa-mobile:ionic-cordova-build --platform=browser` and `cordova build browser --base-href=/ionic/`. Check where the browser `index.html` base tag is generated or handed off, and verify that the resulting tag uses `/ionic/` rather than `/`.

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