bug: Items background colour in Card when active Dark theme

### Prerequisites

- [x] I have read the [Contributing Guidelines](https://github.com/ionic-team/ionic-framework/blob/main/docs/CONTRIBUTING.md#creating-an-issue).
- [x] I agree to follow the [Code of Conduct](https://ionicframework.com/code-of-conduct).
- [x] I have searched for [existing issues](https://github.com/ionic-team/ionic-framework/issues) that already report this problem, without success.

### Ionic Framework Version

v8.x

### Current Behavior

In Dark mode in Card (ion-card) the items (ion-item) have different background than the card.


### Expected Behavior

It should be the same colour as in "light" mode.


### Steps to Reproduce

I forked default "Card with Items" code from official documentation and only changed theme to "dark.always.css".

https://ionicframework.com/docs/api/card#list-card

### Code Reproduction URL

https://stackblitz.com/edit/hp73tq62?file=src%2FApp.vue

### Ionic Info

Ionic:

Ionic CLI : 7.2.0 (/usr/local/lib/node_modules/@ionic/cli)
Ionic Framework : @ionic/vue 8.4.1

Capacitor:

Capacitor CLI : 6.1.2
@capacitor/android : not installed
@capacitor/core : 6.1.2
@capacitor/ios : 6.1.2

Utility:

cordova-res : not installed globally
native-run : 2.0.1

System:

NodeJS : v21.7.3
npm : 10.5.0
OS : macOS Unknown

### Additional Information

_No response_