Title: External Sites (navigation entries with app: "external") stopped opening on tap in 34.x — regression, works fine in 33.1.2

### ⚠️ Before posting ⚠️

- [x] This is a **bug**, not a question or an enhancement.
- [x] I've [searched for similar issues](https://github.com/nextcloud/android/issues) and didn't find a duplicate.
- [x] I've written a clear and descriptive title for this issue, not just "Bug" or "Crash".
- [x] I agree to follow Nextcloud's [Code of Conduct](https://nextcloud.com/contribute/code-of-conduct/).

### Steps to reproduce

1. Configure at least one entry in External Sites (nextcloud/external), either Type: Link (redirect: true) or the default embedded type (redirect: false).
2. Open the official Android app, log in, open the side navigation drawer.
3. Tap the entry.

### Expected behaviour

Entry opens — works in any browser, and in Android app 33.1.2.

### Actual behaviour

On 34.1.0: row highlights (ripple), then nothing. Confirmed via server logs that zero HTTP requests ever reach the target — failure is entirely client-side, pre-network. Reproduces for every entry regardless of redirect true/false, icon, or target host.
What we ruled out

- DNS/reachability — all hosts resolve publicly, work fine in browsers.
- Server bug — found and patched nextcloud/external#769 (https://github.com/nextcloud/external/issues/769) (missing 'app' => 'external' in nav registration) ourselves; no effect on 34.1.0's behaviour.
- Device targeting — device: browser-scoped entries correctly stay hidden on Android, so client detection still works.
- Clean isolation: same server/account/entries — 33.1.2 works, 34.1.0 doesn't.

Couldn't get Logcat (OEM blocks main/system buffer reads on non-rooted ro.debuggable=0 builds), and no in-app logging option found in this version.

### Android version

16

### Device brand and model

Device: RedMagic 10S (NX789J), Android 16 (SDK 36)

### Stock or custom OS?

Stock

### Nextcloud android app version

App broken: 34.1.0 / App working: 33.1.2

### Nextcloud server version

Server: Nextcloud 33.0.6 (snap), External Sites 8.0.1

### Using a reverse proxy?

I don't know

### Android logs

_No response_

### Server error logs

```bash

```

### Additional information

Additional context

34.1.0 released 2026-07-23; reproduces identically for both redirect true/false, suggesting a regression in how 34.x handles taps on non-native drawer entries in general, not something specific to External Sites' payload. Happy to provide the occ config:app:get external sites JSON or log excerpts on request.

Start by reproducing the tap in the side navigation drawer on 34.1.0, then trace how non-native entries with app: "external" are handled and compare that path with 33.1.2. Done means both redirect=true and redirect=false entries open from the drawer without affecting device-hidden entries.

索引モデルが issue の本文から書いたものです。