revert tx data linking behaviour (only take one)

Signed-off-by: Johannes Tuerk <johannes.tuerk@lissi.id>

Author: JoTiTu

src/WalletFramework.Oid4Vc/Oid4Vp/TransactionDatas/TransactionDataFun.cs

@@ -1,7 +1,6 @@
 using LanguageExt;
 using WalletFramework.Core.Base64Url;
 using WalletFramework.Core.Functional;
-using WalletFramework.Core.Functional.Enumerable;
 using WalletFramework.Oid4Vc.Oid4Vp.Errors;
 using WalletFramework.Oid4Vc.Oid4Vp.Models;
 using WalletFramework.Oid4Vc.Oid4Vp.TransactionDatas.Errors;
@@ -123,24 +122,21 @@ internal static Validation<AuthorizationRequestCancellation, PresentationRequest
 
                 foreach (var txData in transactionDatas)
                 {
-                    var findings = indexedCandidates.Where(tuple =>
+                    var found = indexedCandidates.FirstOrDefault(tuple =>
                     {
                         return new[] { tuple.candidate }.FindCandidateForTransactionData(txData).IsSuccess;
-                    }).ToList();
+                    });
 
-                    if (findings.IsEmpty())
+                    if (found == default)
                     {
                         return new InvalidTransactionDataError(
                             $"No credentials found that satisfy the transaction data with type {txData.GetTransactionDataType().AsString()}",
                             presentationRequest).ToInvalid<PresentationRequest>();
                     }
 
                     // Update the candidate with the transaction data
-                    foreach (var found in findings)
-                    {
-                        var updated = found.candidate.AddTransactionDatas([txData]);
-                        updatedCandidates[(found.setIdx, found.candIdx)] = updated;
-                    }
+                    var updated = found.candidate.AddTransactionDatas([txData]);
+                    updatedCandidates[(found.setIdx, found.candIdx)] = updated;
                 }
 
                 // Reconstruct sets with updated candidates