Fix gosec finding of unhandled errors (#29398)

Not critical but fixing it to avoid gosec reporting G104.

devenv/docker/blocks/alert_webhook_listener/main.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
+	"log"
 	"net/http"
 )
 
@@ -15,10 +16,12 @@ func hello(w http.ResponseWriter, r *http.Request) {
 
 	line := fmt.Sprintf("webbhook: -> %s", string(body))
 	fmt.Println(line)
-	io.WriteString(w, line)
+	if _, err := io.WriteString(w, line); err != nil {
+		log.Printf("Failed to write: %v", err)
+	}
 }
 
 func main() {
 	http.HandleFunc("/", hello)
-	http.ListenAndServe(":3010", nil)
+	log.Fatal(http.ListenAndServe(":3010", nil))
 }