Fix issue with the error variant of new_check_header_and_update met…

…hod (#406)

* Return None if ConsensusState not found in new_check_header_and_update_state

* Add changelog entry

.changelog/unreleased/bug-fixes/405-fix-new-check-header-and-update.md

@@ -0,0 +1,3 @@
+- Fix issue with the error handling in the `new_check_header_and_update_state`
+  method when consensus state is not found
+  ([#405](https://github.com/cosmos/ibc-rs/issues/405))

crates/ibc/src/clients/ics07_tendermint/client_state.rs

@@ -692,8 +692,14 @@ impl Ics2ClientState for ClientState {
             match ctx.consensus_state(client_id, &height) {
                 Ok(cs) => Ok(Some(cs)),
                 Err(e) => match e {
+                    ContextError::ClientError(ClientError::ConsensusStateNotFound {
+                        client_id: _,
+                        height: _,
+                    }) => Ok(None),
                     ContextError::ClientError(e) => Err(e),
-                    _ => Ok(None),
+                    _ => Err(ClientError::Other {
+                        description: e.to_string(),
+                    }),
                 },
             }
         }