use account_identifier.kind() instead of hard-coding Ethereum

Author: codabrink

xmtp_id/src/associations/association_log.rs

@@ -87,7 +87,7 @@ impl IdentityAction for CreateInbox {
         }
 
         allowed_signature_for_kind(
-            &MemberKind::Ethereum,
+            &self.account_identifier.kind(),
             &self.initial_identifier_signature.kind,
         )?;