Recover from gas simulation failures on legacy chains (#3793)

Closes: #3792

Co-authored-by: Luca Joss <[email protected]>

.changelog/unreleased/improvements/ibc-relayer-cli/3792-legacy-simulation.md

@@ -0,0 +1,2 @@
+- Recover from gas simulation failures on legacy chains.
+  ([\#3792](https://github.com/informalsystems/hermes/issues/3792))

crates/relayer/src/chain/cosmos/estimate.rs

@@ -190,6 +190,7 @@ fn can_recover_from_simulation_failure(e: &Error) -> bool {
             detail.is_client_state_height_too_low()
                 || detail.is_account_sequence_mismatch_that_can_be_ignored()
                 || detail.is_out_of_order_packet_sequence_error()
+                || detail.is_empty_tx_error()
         }
         _ => false,
     }

crates/relayer/src/error.rs

@@ -709,6 +709,14 @@ impl GrpcStatusSubdetail {
             Some((expected, got)) => expected < got,
         }
     }
+
+    /// Check whether this gRPC error message contains the string "invalid empty tx".
+    ///
+    /// ## Note
+    /// This error may happen for older chains that does not properly support simulation.
+    pub fn is_empty_tx_error(&self) -> bool {
+        self.status.message().contains("invalid empty tx")
+    }
 }
 
 /// Assumes that the cosmos-sdk account sequence mismatch error message, that may be seen