Partial columns cleanup (#9321)

#8314 left a few ugly potentially panicking location behind - all of them believed to be unreachable, but this PR fixes them regardless for good hygiene.


  Update to `ethereum_ssz 0.10.4` for two new helpers: `not_inplace` and `clone_zeroed`.

Remove remaining `expect` and `todo!` in favour of these helpers and one new fallible (but practically infallible) method.


Co-Authored-By: Daniel Knopik <daniel@dknopik.de>

beacon_node/network/src/network_beacon_processor/gossip_methods.rs

@@ -1381,16 +1381,20 @@ impl<T: BeaconChainTypes> NetworkBeaconProcessor<T> {
                 &[&data_column_index.to_string()],
             );
 
-            let mut column = col.to_partial();
-            let header = column.sidecar.header.take();
-            if let Some(header) = header {
-                self.send_network_message(NetworkMessage::PublishPartialColumns {
-                    columns: vec![Arc::new(column)],
-                    header: Arc::new(header),
-                });
-            } else {
-                crit!("Converting from full to partial yielded headerless partial")
-            };
+            match col.to_partial() {
+                Ok(mut column) => {
+                    let header = column.sidecar.header.take();
+                    if let Some(header) = header {
+                        self.send_network_message(NetworkMessage::PublishPartialColumns {
+                            columns: vec![Arc::new(column)],
+                            header: Arc::new(header),
+                        });
+                    } else {
+                        crit!("Converting from full to partial yielded headerless partial")
+                    };
+                }
+                Err(err) => crit!(?err, "Could not convert from full to partial"),
+            }
         }
 
         let result = self