10 rules skipped due to selector errors

`ionic build --prod`

```
Generating index html...10 rules skipped due to selector errors:
:host-context([dir=rtl]) .ion-float-start -> unmatched pseudo-class :host-context
:host-context([dir=rtl]) .ion-float-end -> unmatched pseudo-class :host-context
:host-context([dir=rtl]) .ion-float-sm-start -> unmatched pseudo-class :host-context
:host-context([dir=rtl]) .ion-float-sm-end -> unmatched pseudo-class :host-context
:host-context([dir=rtl]) .ion-float-md-start -> unmatched pseudo-class :host-context
:host-context([dir=rtl]) .ion-float-md-end -> unmatched pseudo-class :host-context
:host-context([dir=rtl]) .ion-float-lg-start -> unmatched pseudo-class :host-context
:host-context([dir=rtl]) .ion-float-lg-end -> unmatched pseudo-class :host-context
:host-context([dir=rtl]) .ion-float-xl-start -> unmatched pseudo-class :host-context
:host-context([dir=rtl]) .ion-float-xl-end -> unmatched pseudo-class :host-context
✔ Index html generation complete.
```

ionic info

```
Ionic:

Ionic CLI : 6.16.3 (C:\Users\Sampath\AppData\Roaming\npm\node_modules\@ionic\cli)
Ionic Framework : @ionic/angular 5.6.13
@angular-devkit/build-angular : 12.1.4
@angular-devkit/schematics : 12.1.4
@angular/cli : 12.1.4
@ionic/angular-toolkit : 4.0.0

Capacitor:

Capacitor CLI : 3.1.2
@capacitor/android : 3.1.2
@capacitor/core : 3.2.0
@capacitor/ios : 3.2.0

Utility:

cordova-res : 0.15.3
native-run : 1.4.0

System:

NodeJS : v14.16.1 (C:\Program Files\nodejs\node.exe)
npm : 6.14.12
OS : Windows 10
```

Start by reproducing `ionic build --prod` with the Ionic, Angular CLI, Node.js, and Windows versions listed in the issue. Trace where the ten `:host-context` selector errors are emitted and determine whether the build is expected to process or skip them; done requires an agreed resolution for the skipped rules and a verified production build.

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