[Bug] @capacitor/browser popover is broken on iOS 27

## Bug Report

### Plugin(s)

@capacitor/browser 8.0.4

### Capacitor Version

```
Latest Dependencies:

@capacitor/cli: 8.5.1
@capacitor/core: 8.5.1
@capacitor/android: 8.5.1
@capacitor/ios: 8.5.1

Installed Dependencies:

@capacitor/core: 8.5.1
@capacitor/android: 8.5.1
@capacitor/cli: 8.5.1
@capacitor/ios: 8.5.1
```

### Platform(s)

iOS, iPad only (reproduced on iPadOS 27)

### Current Behavior

`Browser.open` with `presentationStyle: 'popover'` shows the popover, but the SFSafariViewController inside stays blank: no content, back button disabled. This happens with and without `width`/`height`. The `open()` call is logged (`To Native -> Browser open`) and the page never appears.

### Expected Behavior

The URL loads and shows inside the popover, as it does with `presentationStyle: 'fullscreen'`.

### Code Reproduction

```ts
import { Browser } from '@capacitor/browser';

await Browser.open({ url: 'https://example.com', presentationStyle: 'popover' });
```

Run it on an iPad with iPadOS 27: the popover is blank. Remove `presentationStyle` (fullscreen) and the page loads.

### Additional Context

Workaround: use the default fullscreen presentation.

Reproduce the issue with Browser.open using presentationStyle: 'popover' on an iPad running iPadOS 27, then compare it with fullscreen presentation. Start at the iOS Browser implementation that presents SFSafariViewController; done means the popover loads the URL and behaves like the fullscreen version, including an enabled back button.

Written by the indexing model from the issue text.