fix GetRegisteredPayload cell conversion failure

- iterate through all tables instead of the first only
- use ToFreeTextCell(), which is a proper conversion instead of AsFreeTextCell which is a match that can fail

src/ARCtrl/ARCtrl.fs

@@ -276,10 +276,12 @@ type ARC(?isa : ISA.ArcInvestigation, ?cwl : CWL.CWL, ?fs : FileSystem.FileSyste
                     yield $"{studyFoldername}/README.md"
 
                     //just allow any constructed path from cell values. there may be occasions where this includes wrong files, but its good enough for now.
-                    for (kv) in s.Tables[0].Values do
-                        yield kv.Value.AsFreeText // from arc root
-                        yield $"{studyFoldername}/resources/{kv.Value.AsFreeText}" // from study root > resources
-                        yield $"{studyFoldername}/protocols/{kv.Value.AsFreeText}" // from study root > protocols
+                    for table in s.Tables do
+                        for kv in table.Values do
+                            let textValue = kv.Value.ToFreeTextCell().AsFreeText
+                            yield textValue // from arc root
+                            yield $"{studyFoldername}/resources/{textValue}" // from study root > resources
+                            yield $"{studyFoldername}/protocols/{textValue}" // from study root > protocols
                 ]
             )
             |> Set.unionMany
@@ -294,10 +296,12 @@ type ARC(?isa : ISA.ArcInvestigation, ?cwl : CWL.CWL, ?fs : FileSystem.FileSyste
                     yield $"{assayFoldername}/README.md"
 
                     //just allow any constructed path from cell values. there may be occasions where this includes wrong files, but its good enough for now.
-                    for (kv) in a.Tables[0].Values do
-                        yield kv.Value.AsFreeText // from arc root
-                        yield $"{assayFoldername}/dataset/{kv.Value.AsFreeText}" // from assay root > dataset
-                        yield $"{assayFoldername}/protocols/{kv.Value.AsFreeText}" // from assay root > protocols
+                    for table in a.Tables do
+                        for kv in table.Values do
+                            let textValue = kv.Value.ToFreeTextCell().AsFreeText
+                            yield textValue // from arc root
+                            yield $"{assayFoldername}/dataset/{textValue}" // from assay root > dataset
+                            yield $"{assayFoldername}/protocols/{textValue}" // from assay root > protocols
                 ]
             )
             |> Set.unionMany