[BUG] install fail silently (edge case for INSTALL_FAILED_UPDATE_INCOMPATIBLE)

### Before you submit

- [x] I have searched the issue tracker for [open](https://github.com/Droid-ify/client/issues) and [closed](https://github.com/Droid-ify/client/issues?q=is%3Aissue+is%3Aclosed) issues that are similar to the feature request I want to file, without success.
- [x] This issue contains only one bug.

### What's going wrong?

Installation fails silently when there is a signature mismatch.

### How do we reproduce it?

NOTE: reproduction steps require [Device Owner](https://source.android.com/docs/devices/admin) or [Dhizuku](https://github.com/iamr0s/Dhizuku) privileges

1. Build a debug version of any app that exists on F-Droid (or just build with a different signature). In my case, I used my app [Webview Kiosk](https://github.com/nktnet1/webview-kiosk).

2. Download either [OwnDroid](https://github.com/BinTianqi/OwnDroid) or [Test DPC](https://github.com/googlesamples/android-testdpc) - I used OwnDroid. Then

- grant OwnDroid either Device Owner or Dhizuku access
- click "Applications", find the app in step 1, then toggle the switch "Keep after uninstall"

3. Uninstall the app

4. Find the app on Droid-ify and attempt to install it

5. Observe that the final installation step stops abruptly with no errors/warnings

---

If you perform step 4 with the official F-Droid app, you will see an error about signature mismatch:

> INSTALL_FAILED_UPDATE_INCOMPATIBLE: Existing package uk.nktnet.webviewkiosk signatures to not match newer version; ignoring!

### What did you expect?

Show an error similar to the official F-Droid app store. It looks like the error display already exists in #1107 - just not showing.

### Screenshots

1. OwnDroid keep after uninstall:

 

2. F-Droid correctly display error:

### Your phone

[Samsung Galaxy S21](https://www.samsung.com/uk/smartphones/galaxy-s21-ultra-5g/specs/)

### Android version

15

### Droid-ify version

0.7.1

### Anything else?

As an aside, even if we toggle the "Incompatible versions" settings in Droid-ify, it still fails silently.