fix: use http response writer directly

Fixes an issue with fmt.Fprint formatting byte arrays.

Signed-off-by: bzub <bzub@users.noreply.github.com>
Signed-off-by: Andrey Smirnov <andrey.smirnov@talos-systems.com>
(cherry picked from commit 3eddbbd)

app/sidero-controller-manager/internal/ipxe/ipxe_server.go

@@ -120,7 +120,7 @@ var (
 )
 
 func bootFileHandler(w http.ResponseWriter, r *http.Request) {
-	fmt.Fprint(w, embeddedScriptBuf.Bytes())
+	w.Write(embeddedScriptBuf.Bytes())
 }
 
 //nolint:unparam