Fix concurrent on userStrategies

src/Managing.Application.Abstractions/Services/ITradingService.cs

@@ -37,6 +37,7 @@ public interface ITradingService
     Task<IEnumerable<Position>> GetBrokerPositions(Account account);
     Task<IEnumerable<Position>> GetAllDatabasePositionsAsync();
     Task<IEnumerable<Position>> GetPositionsByInitiatorIdentifierAsync(Guid initiatorIdentifier);
+    Task<IEnumerable<Position>> GetPositionsByInitiatorIdentifiersAsync(IEnumerable<Guid> initiatorIdentifiers);
     Task<PrivyInitAddressResponse> InitPrivyWallet(string publicAddress);
 
     // Synth API integration methods