fix(deps): bump @girs/gjs from 4.0.0-beta.16 to 4.0.0-beta.21 (#604)

Bumps [@girs/gjs](https://github.com/gjsify/ts-for-gir) from 4.0.0-beta.16 to 4.0.0-beta.21.
- [Release notes](https://github.com/gjsify/ts-for-gir/releases)
- [Changelog](https://github.com/gjsify/ts-for-gir/blob/main/NEWS.md)
- [Commits](gjsify/ts-for-gir@4.0.0-beta.16...v4.0.0-beta.21)

---
updated-dependencies:
- dependency-name: "@girs/gjs"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

extensions/gnome-extension/package.json

@@ -22,7 +22,7 @@
     "typescript-eslint": "^8.20.0"
   },
   "dependencies": {
-    "@girs/gjs": "4.0.0-beta.16",
+    "@girs/gjs": "4.0.0-beta.21",
     "@girs/gnome-shell": "^46.0.2"
   },
   "sideEffects": false