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

packages/playwright-tests/default-features-disabled/src/main.rs

@@ -0,0 +1,42 @@
+// This test asserts that the client feature is disable on the server build by the cli
+// even if it is set as a default feature
+
+#![allow(non_snake_case)]
+use dioxus::prelude::*;
+
+fn main() {
+    launch(app);
+}
+
+fn app() -> Element {
+    let server_features = use_server_future(get_server_features)?.unwrap().unwrap();
+    let mut client_features = use_signal(Vec::new);
+    use_effect(move || {
+        client_features.set(current_platform_features());
+    });
+
+    rsx! {
+        div {
+            "server features: {server_features:?}"
+        }
+        div {
+            "client features: {client_features:?}"
+        }
+    }
+}
+
+fn current_platform_features() -> Vec<String> {
+    let mut features = Vec::new();
+    if cfg!(feature = "web") {
+        features.push("web".to_string());
+    }
+    if cfg!(feature = "server") {
+        features.push("server".to_string());
+    }
+    features
+}
+
+#[server]
+async fn get_server_features() -> Result<Vec<String>, ServerFnError> {
+    Ok(current_platform_features())
+}