feat: make Unity integration optional

Development~/UnityProject/Packages/manifest.json

@@ -1,13 +1,4 @@
 {
-  "scopedRegistries": [
-    {
-      "name": "ShrinkSDK",
-      "url": "https://git.crash.work/api/packages/ShrinkSDK/npm/",
-      "scopes": [
-        "com.cneicy"
-      ]
-    }
-  ],
   "dependencies": {
     "com.unity.test-framework": "1.1.33",
     "com.cneicy.shrink-eventbus": "file:../../..",