Bump electron from 25.3.0 to 25.8.4 in /gui

Bumps [electron](https://github.com/electron/electron) from 25.3.0 to 25.8.4.
- [Release notes](https://github.com/electron/electron/releases)
- [Changelog](https://github.com/electron/electron/blob/main/docs/breaking-changes.md)
- [Commits](electron/electron@v25.3.0...v25.8.4)

---
updated-dependencies:
- dependency-name: electron
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <support@github.com>

gui/package.json

@@ -62,7 +62,7 @@
     "babel-plugin-transform-react-remove-prop-types": "^0.4.24",
     "cross-env": "^7.0.3",
     "css-loader": "^6.8.1",
-    "electron": "^25.3.0",
+    "electron": "^25.8.4",
     "electron-devtools-installer": "^3.2.0",
     "file-loader": "^6.2.0",
     "html-webpack-plugin": "^5.5.3",