fix(cardano-services): don't fetch assets for collateralReturn as if it was an output

Author: iccicci

packages/cardano-services/src/ChainHistory/DbSyncChainHistory/ChainHistoryBuilder.ts

@@ -261,7 +261,7 @@ export class ChainHistoryBuilder {
     if (result.rows.length === 0) return [];
 
     const txOutIds = result.rows.flatMap((txOut) => BigInt(txOut.id));
-    const multiAssets = await this.queryMultiAssetsByTxOut(txOutIds);
+    const multiAssets = collateral ? new Map() : await this.queryMultiAssetsByTxOut(txOutIds);
     const referenceScripts = await this.queryReferenceScriptsByTxOut(result.rows);
 
     return result.rows.map((txOut) =>