Revert "chore(deps): update pnpm to v10.12.4 (#1033)"

This reverts commit a815e2f4b7.

Since updating pnpm, release builds do not work anymore. Reverting this
commit until we have a proper fix.

desktop/package.json

@@ -5,7 +5,7 @@
   "main": "main.js",
   "repository": "https://code.vikunja.io/desktop",
   "license": "GPL-3.0-or-later",
-  "packageManager": "pnpm@10.12.4",
+  "packageManager": "pnpm@10.12.3",
   "author": {
     "email": "maintainers@vikunja.io",
     "name": "Vikunja Team"

frontend/package.json

@@ -13,7 +13,7 @@
   },
   "homepage": "https://vikunja.io/",
   "funding": "https://opencollective.com/vikunja",
-  "packageManager": "pnpm@10.12.4",
+  "packageManager": "pnpm@10.12.3",
   "keywords": [
     "todo",
     "productivity",