fixup! Passing binary payloads to flows

Author: didier-wenzek

crates/extensions/tedge_flows/src/flow.rs

@@ -256,9 +256,7 @@ impl Message {
 
 impl std::fmt::Display for Message {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        '['.fmt(f)?;
-        self.topic.fmt(f)?;
-        "] ".fmt(f)?;
+        write!(f, "[{}] ", self.topic)?;
         match &self.payload_str() {
             Some(str) => str.fmt(f),
             None => format!("{:?}", self.payload).fmt(f),