desktop: add support for running tests in parallel

we do this by copying the build directory instead of building it over and over
again for each test. This also makes the tests super fast.

apps/desktop/package.json

@@ -8,7 +8,9 @@
   "main": "./dist/cjs/index.js",
   "module": "./dist/esm/index.js",
   "types": "./dist/types/index.d.ts",
-  "sideEffects": false,
+  "sideEffects": [
+    "src/overrides.ts"
+  ],
   "exports": {
     ".": {
       "require": {