Do not ignore task cancelled exceptions from sharepoint sdk (#555)

src/FlowtideDotNet.Connector.Sharepoint/Internal/SharepointSource.cs

@@ -88,15 +88,29 @@ private async Task FetchDelta(IngressOutput<StreamEventBatch> output, object? st
 
             Logger.BeforeCheckpointInDelta(StreamName, Name);
             await output.EnterCheckpointLock();
-            Logger.FetchingDelta(StreamName, Name);
-            if (await HandleDataRows(iterator, output))
+            try
             {
-                _state.WatermarkVersion++;
-                await output.SendWatermark(new Base.Watermark(readRelation.NamedTable.DotSeperated, _state.WatermarkVersion));
-
-                ScheduleCheckpoint(TimeSpan.FromMilliseconds(1));
+                Logger.FetchingDelta(StreamName, Name);
+                if (await HandleDataRows(iterator, output))
+                {
+                    _state.WatermarkVersion++;
+                    await output.SendWatermark(new Base.Watermark(readRelation.NamedTable.DotSeperated, _state.WatermarkVersion));
+
+                    ScheduleCheckpoint(TimeSpan.FromMilliseconds(1));
+                }
+            }
+            catch(Exception e)
+            {
+                Logger.LogError(e, "Error fetching delta");
+                if (e is TaskCanceledException || e is OperationCanceledException)
+                {
+                    throw new InvalidOperationException("Error fetching delta, task was cancelled.", e);
+                }
+            }
+            finally
+            {
+                output.ExitCheckpointLock();
             }
-            output.ExitCheckpointLock();
         }
 
         protected override Task<IReadOnlySet<string>> GetWatermarkNames()