Wrap command tcpstates-bpfcc with `python3 -u` in forwarder_guest_launcher

Bug: 340126051
Test: Compare result w/ and  w/o `python3 -u` command.
Change-Id: I44da5cba50fcc2413e5fe16576e4afdd2dda5303
diff --git a/guest/forwarder_guest_launcher/src/main.rs b/guest/forwarder_guest_launcher/src/main.rs
index 0e06c66..bba9691 100644
--- a/guest/forwarder_guest_launcher/src/main.rs
+++ b/guest/forwarder_guest_launcher/src/main.rs
@@ -110,8 +110,11 @@
 async fn report_active_ports(
     mut client: DebianServiceClient<Channel>,
 ) -> Result<(), Box<dyn std::error::Error>> {
-    let mut cmd =
-        Command::new("/usr/sbin/tcpstates-bpfcc").arg("-s").stdout(Stdio::piped()).spawn()?;
+    let mut cmd = Command::new("python3")
+        .arg("-u")
+        .arg("/usr/sbin/tcpstates-bpfcc -s")
+        .stdout(Stdio::piped())
+        .spawn()?;
     let stdout = cmd.stdout.take().context("Failed to get stdout of tcpstates")?;
     let mut csv_reader = AsyncReader::from_reader(BufReader::new(stdout));
     let header = csv_reader.headers().await?.clone();