fix(ci): drop e2e pnpm version override

pnpm/action-setup@v4 fails when both `with.version` and the
`packageManager` field in package.json declare a pnpm version.
Removing the workflow override and letting the action read
`packageManager: pnpm@10.31.0` from package.json is the canonical
fix and matches the integration / security workflows.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.github/workflows/e2e.yml

@@ -44,8 +44,6 @@ jobs:
       - uses: actions/checkout@v4
 
       - uses: pnpm/action-setup@v4
-        with:
-          version: 10
 
       - uses: actions/setup-node@v4
         with: