Do not allow overriding an intent that is already published (#1416)

* log payload hash after successfully saving commit

* hex encode payload slice before logging

* do not allow overriding an intent that is already published

* remove extra log and format

---------

Co-authored-by: cameronvoell <cameronvoell@users.noreply.github.com>

xmtp_mls/src/storage/encrypted_store/group_intent.rs

@@ -202,11 +202,7 @@ impl DbConnection {
                 .filter(dsl::id.eq(intent_id))
                 // State machine requires that the only valid state transition to Published is from
                 // ToPublish
-                .filter(
-                    dsl::state
-                        .eq(IntentState::ToPublish)
-                        .or(dsl::state.eq(IntentState::Published)),
-                )
+                .filter(dsl::state.eq(IntentState::ToPublish))
                 .set((
                     dsl::state.eq(IntentState::Published),
                     dsl::payload_hash.eq(payload_hash),