message: ensure lowest block height is set correctly on early exit from sync
diff: @@ -915,6 +915,9 @@ async fn fetch_to_genesis(trusted_block: &Block, ctx: &ChainSyncContext<'_>) ->
  .await;
  if let Some(lowest_available_block) = maybe_lowest_available_block {
  if lowest_available_block.height() == 0 {
  + ctx.effect_builder
  + .update_lowest_available_block_height_in_storage(0)
  + .await;
  break;
  }
  walkback_block = *fetch_and_store_block_by_hash(
  