[OS7]Incorrect screenshot URL returned for some apps

### What Happened?

Viewing some apps such as Files and Terminal fails to show any screenshots even thought screenshots are available on GitHub.

Some investigation showed that the URL from which the FIles screenshots were trying to be downloaded were such as:
`io/elementary/files/F94D1CA03544E8EC7862C65BE3F1060E/screenshots/image-1_1248x821.png`

whereas the screenshots are actually available at e.g. `https://raw.githubusercontent.com/elementary/files/master/data/screenshot-grid.png` as detailed in the appdata.

This may be an upstream or packaging issue.

### Steps to Reproduce

Open AppCenter
Navigate to FIles AppInfo
Observe no screenshots

### Expected Behavior

Screenshots are show where available.

### OS Version

7.x (Early Access)

### Software Version

Compiled from git

### Log Output

```shell
Some extra debugging code gave the following:

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.460: ScreenshotCache.vala:147: generate screenshot path from io/elementary/files/F94D1CA03544E8EC7862C65BE3F1060E/screenshots/image-3_1248x821.png

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.461: AppInfoView.vala:998: fetching url io/elementary/files/F94D1CA03544E8EC7862C65BE3F1060E/screenshots/image-2_1248x821.png

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.461: ScreenshotCache.vala:147: generate screenshot path from io/elementary/files/F94D1CA03544E8EC7862C65BE3F1060E/screenshots/image-2_1248x821.png

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.461: AppInfoView.vala:998: fetching url io/elementary/files/F94D1CA03544E8EC7862C65BE3F1060E/screenshots/image-1_1248x821.png

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.461: ScreenshotCache.vala:147: generate screenshot path from io/elementary/files/F94D1CA03544E8EC7862C65BE3F1060E/screenshots/image-1_1248x821.png

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.472: ScreenshotCache.vala:194: Error getting modification time of remote screenshot file: Operation not supported

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.472: ScreenshotCache.vala:216: try to download screenshot from io/elementary/files/F94D1CA03544E8EC7862C65BE3F1060E/screenshots/image-3_1248x821.png

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.472: ScreenshotCache.vala:194: Error getting modification time of remote screenshot file: Operation not supported

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.472: ScreenshotCache.vala:216: try to download screenshot from io/elementary/files/F94D1CA03544E8EC7862C65BE3F1060E/screenshots/image-1_1248x821.png

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.472: ScreenshotCache.vala:194: Error getting modification time of remote screenshot file: Operation not supported

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.472: ScreenshotCache.vala:216: try to download screenshot from io/elementary/files/F94D1CA03544E8EC7862C65BE3F1060E/screenshots/image-2_1248x821.png

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.472: ScreenshotCache.vala:236: Unable to download screenshot from io/elementary/files/F94D1CA03544E8EC7862C65BE3F1060E/screenshots/image-3_1248x821.png: Operation not supported

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.472: ScreenshotCache.vala:236: Unable to download screenshot from io/elementary/files/F94D1CA03544E8EC7862C65BE3F1060E/screenshots/image-1_1248x821.png: Operation not supported

** (io.elementary.appcenter:40969): WARNING **: 16:33:25.473: ScreenshotCache.vala:236: Unable to download screenshot from io/elementary/files/F94D1CA03544E8EC7862C65BE3F1060E/screenshots/image-2_1248x821.png: Operation not supported

(io.elementary.appcenter:40969): Gtk-WARNING **: 16:33:26.648: gtk_widget_size_allocate(): attempt to allocate widget with width -5 and height 16
```
```

### Hardware Info

_No response_