Merged PR 729798: Demote timeout and missing blob error traces in cache code

Seen in AnyBuild telemetry.

```
Failed to obtain properties from latest blob at path checkpoints:checkpointRegistry/rg-a01835ca5c25429f85223a4479a6022drg-a01835ca5c25429f85223a4479a6022d_20230413rg-a01835ca5c25429f85223a4479a6022d_20230413.latest.json.: Azure.RequestFailedException: Service request failed.
Status: 404 (The specified blob does not exist.)
ErrorCode: BlobNotFound
```

```
Error during ReceiveBatchAsync: System.Threading.Tasks.TaskCanceledException: A task was canceled.
   at Microsoft.Azure.Amqp.AsyncResult.End[TAsyncResult](IAsyncResult result)
```

Author: erikmav

Public/Src/Cache/ContentStore/Distributed/NuCache/AzureBlobStorageCheckpointRegistry.cs

@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.Diagnostics.ContractsLight;
 using System.Linq;
+using System.Net;
 using System.ServiceModel.Description;
 using System.Text.RegularExpressions;
 using System.Threading;
@@ -145,6 +146,11 @@ public Task<Result<CheckpointState>> GetCheckpointStateAsync(OperationContext co
                             // Breaking from the loop instead of tracing error for each iteration.
                             break;
                         }
+                        catch (Azure.RequestFailedException reqEx) when (reqEx.Status == (int)HttpStatusCode.NotFound)
+                        {
+                            Tracer.Debug(context, $"Failed to obtain {nameof(CheckpointState)} - missing blob `{blob.ToDisplayName()}`. Skipping.");
+                            continue;
+                        }
                         catch (Exception e)
                         {
                             Tracer.Error(context, e, $"Failed to obtain {nameof(CheckpointState)} from blob `{blob.ToDisplayName()}`. Skipping.");

Public/Src/Cache/ContentStore/Distributed/NuCache/EventStreaming/PartitionReceiverWrapper.cs

@@ -131,9 +131,26 @@ private async Task ReceivePumpAsync(OperationContext context, CancellationToken
                         // ConsumerDisconnectedException is a special case where we know we cannot recover the pump.
                         break;
                     }
+                    catch (OperationCanceledException) when (cancellationToken.IsCancellationRequested)
+                    {
+                        // Breaking from the loop instead of tracing error for each iteration.
+                        break;
+                    }
+                    catch (OperationCanceledException)
+                    {
+                        // One form of timeout.
+                        // Breaking from the loop instead of tracing error for each iteration.
+                        break;
+                    }
+                    catch (TimeoutException)
+                    {
+                        // Another form of timeout.
+                        // Breaking from the loop instead of tracing error for each iteration.
+                        break;
+                    }
                     catch (Exception e)
                     {
-                        Tracer.Error(context, e, "Error during ReceiveBatchAsync");
+                        Tracer.Error(context, e, $"Error during {nameof(ReceiveBatchAsync)}");
                         continue;
                     }