Bug-fix: identify already exists errors correctly while creating assertions (#3875)

Author: ganeshvanahalli

bold/chain-abstraction/sol-implementation/assertion_chain.go

@@ -661,7 +661,7 @@ func (a *AssertionChain) createAndStakeOnAssertion(
 	})
 	opts := a.GetCallOptsWithDesiredRpcHeadBlockNumber(&bind.CallOpts{Context: ctx})
 	if createErr := handleCreateAssertionError(err, postState.GlobalState.BlockHash); createErr != nil {
-		if strings.Contains(err.Error(), "already exists") {
+		if strings.Contains(createErr.Error(), "already exists") {
 			assertionItem, err2 := a.GetAssertion(ctx, opts, protocol.AssertionHash{Hash: computedHash})
 			if err2 != nil {
 				return nil, err2