Update etag reset logic in the checkpoint store (Azure#48244)

Author: jeo02

sdk/eventhub/Azure.Messaging.EventHubs.Shared/src/BlobCheckpointStore/BlobCheckpointStoreInternal.cs

@@ -223,9 +223,11 @@ public override async Task<IEnumerable<EventProcessorPartitionOwnership>> ClaimO
                         {
                             // This is an unlikely corner case that indicates that the blob was unexpectedly deleted while the
                             // processor is running.  Attempt to recover by resetting the ETag and considering it an upload scenario
-                            // to be handled by the next block.
+                            // to be handled by the next block. Additionally clear the IfMatch to ensure next block does not have
+                            // an outdated ETag.
 
                             ownership.Version = null;
+                            blobRequestConditions.IfMatch = null;
                         }
                     }
 

sdk/eventhub/Azure.Messaging.EventHubs.Shared/tests/BlobCheckpointStore/BlobsCheckpointStoreInternalTests.cs

@@ -309,9 +309,11 @@ public async Task ClaimOwnershipCompensatesWhenABlobIsDeleted()
                     setMetadataCalled = true;
                 };
 
-                client.UploadAsyncCallback = (_, _, _, _, _, _, _, _) =>
+                client.UploadAsyncCallback = (_, _, _, conditions, _, _, _, _) =>
                 {
                     uploadBlobCalled = true;
+                    Assert.That(conditions.IfNoneMatch, Is.EqualTo(new ETag("*")), "The IfNoneMatch condition should be set.");
+                    Assert.That(conditions.IfMatch, Is.Null, "The IfMatch condition should be null.");
                 };
             });