Fix nx configuration to actually run type linter (#32776)

* do not indirect tsc commands via tsc

Currently, `nx lint:types` is configured to indirect its `tsc` incantations via
pnpm. As far as I can tell, this is unnecessary; worse, it means we seem to hit
a pnpm reentrancy bug which causes pnpm not to run those commands at all if the
top level pnpm has `--if-present`.

* Reinstate indirection via pnpm

... to evade knip.

apps/web/project.json

@@ -34,9 +34,12 @@
             "executor": "nx:run-commands",
             "options": {
                 "commands": [
-                    "pnpm tsc --noEmit --project ./tsconfig.module_system.json",
-                    "pnpm tsc --noEmit",
-                    "pnpm tsc --noEmit -p playwright"
+                    // We indirect via `pnpm exec` to stop knip interpreting the
+                    // commandline and declaring `playwright` and `./tsconfig.module_system.json`
+                    // as unlisted dependencies.
+                    "pnpm exec tsc --noEmit --project ./tsconfig.module_system.json",
+                    "pnpm exec tsc --noEmit",
+                    "pnpm exec tsc --noEmit --project playwright"
                 ],
                 "parallel": false,
                 "cwd": "apps/web"