Undo pnpm v9, don't hoist opencollective-postinstall

.npmrc

@@ -1,8 +1,3 @@
 # Make sure the default patterns are still included (https://pnpm.io/npmrc#public-hoist-pattern)
 public-hoist-pattern[]="*eslint*"
 public-hoist-pattern[]="*prettier*"
-
-# This is only necessary in this repo because pnpm symlinks the sku dependency in fixtures to the sku package folder directly
-# This bypasses the .pnpm folder that resolveModules looks for
-# See https://github.com/seek-oss/sku/blob/275752bd3066e52885d461ef5bcd953aaac3bfff/config/webpack/resolveModules.js
-public-hoist-pattern[]="@babel/*"

package.json

@@ -69,7 +69,7 @@
   },
   "volta": {
     "node": "18.16.0",
-    "pnpm": "9.1.0"
+    "pnpm": "8.15.8"
   },
   "packageManager": "pnpm@9.1.0",
   "skuSkipPostInstall": true,