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/cli/src/build/request.rs

@@ -92,7 +92,7 @@ impl BuildRequest {
     pub(crate) async fn build_server(&self) -> Result<Option<BuildArtifacts>> {
         tracing::debug!("Building server...");
 
-        if !self.build.fullstack {
+        if !self.build.fullstack() {
             return Ok(None);
         }