Remove default features when fullstack is enabled and one platform is enabled in the default features (#3925)

* Don't enable default features when only either the server or client is enabled

Cargo.toml

@@ -103,6 +103,7 @@ members = [
     "packages/playwright-tests/nested-suspense",
     "packages/playwright-tests/cli-optimization",
     "packages/playwright-tests/wasm-split-harness",
+    "packages/playwright-tests/default-features-disabled"
 ]
 
 [workspace.package]