BUG: Flickering icons in Plugin Store

### Checks

- [x] I have checked that this issue has not already been reported.

- [x] I am using the latest version of Flow Launcher.

- [x] I am using the prerelease version of Flow Launcher.

### Problem Description

Icons of plugins in the Installed section of the plugin store flicker when you scroll past them.

The completely missing icons should probably be treated as a separate issue - potentially related to the CDNs used.

This happens both in the dev branch and current release

### To Reproduce

It seems to reliably happen when you first open the plugin store and then scroll all the way down to installed plugins
Then scroll up and down a bit to see the effect

### Screenshots

https://github.com/user-attachments/assets/23ac4bc7-105d-499f-bdd9-5d6c30e7d01a

### Flow Launcher Version

2.1.3

### Windows Build Number

10.0.26200.8737

### Error Log

```shell

Replace this line with the important log contents.

```

Start by opening the Plugin Store, scrolling to the Installed section, and scrolling up and down as described to reproduce the flicker. Trace the Installed plugin icon rendering path in the desktop application; done means installed plugin icons remain stable while scrolling, while the separate missing-icon problem remains out of scope.

Written by the indexing model from the issue text.