fix(ci): qa-gate — remove duplicate pnpm version pin

pnpm/action-setup@v4 conflicts when both workflow `version: 10` and
package.json `"packageManager": "pnpm@10.29.3"` are set. Drop the
workflow pin and let action-setup read packageManager.

Unblocks the QA gate workflow on PRs (was failing in setup before
tests ran, e.g. run 25784218896).

.github/workflows/qa-gate.yml

@@ -23,8 +23,6 @@ jobs:
           fetch-depth: 0
 
       - uses: pnpm/action-setup@v4
-        with:
-          version: 10
 
       - uses: actions/setup-node@v4
         with: