Blob_SetMetadata： Fail with 403 when use HttpRequestHandler.SetHeader in request OperationContext

### Which service(blob, file, queue, table) does this issue concern?
blob
### Which version of the Azurite was used?
3.3.0-preview
### Where do you get Azurite? (npm, DockerHub, NuGet, Visual Studio Code Extension)
VS code
### What's the Node.js version?
v10.15.3
### What problem was encountered?
Blob_SetMetadata： Fail with 403 when use HttpRequestHandler.SetHeader in request OperationContext
### Steps to reproduce the issue?
```
var blobName = GetRandomBlobName();
CloudPageBlob blob = container.GetPageBlobReference(blobName);
CloudPageBlob blob2 = container.GetPageBlobReference(blobName);
blob.Create(1024);
blob.Metadata["key1"] = "value1";

OperationContext context = new OperationContext();
context.SendingRequest += (sender, e) =>
{
HttpRequestHandler.SetHeader(e.Request, "x-ms-meta-key1", string.Empty);
};

blob.SetMetadata(operationContext: context);
```
### Have you found a mitigation/solution?
No

Debug Log:
```
2019-12-18T03:05:04.022Z 4924342c-6234-433f-86df-ad99296838ac info: BlobStorageContextMiddleware: RequestMethod=PUT RequestURL=http://127.0.0.1/devstoreaccount1/testcb6019b7f8e4b4b1baeb044b072c5e915/testb63b649aca6764f039677b52ca75e459c?comp=metadata RequestHeaders:{"x-ms-meta-key1":"value1, ","x-ms-client-request-id":"9a3ffec7-23e5-45f9-9716-75749ee73d30","user-agent":"Azure-Storage/11.1.1 (.NET Core; Win32NT 6.2.9200.0)","x-ms-version":"2019-02-02","x-ms-date":"Wed, 18 Dec 2019 03:05:04 GMT","authorization":"SharedKey devstoreaccount1:8Xoa5/7XN8DK4RB1yAkVIYDW5vmbdXGVdVKrIYKiO+E=","content-length":"0","host":"127.0.0.1:10000"} ClientIP=127.0.0.1 Protocol=http HTTPVersion=1.1
2019-12-18T03:05:04.023Z 4924342c-6234-433f-86df-ad99296838ac info: BlobStorageContextMiddleware: Account=devstoreaccount1 Container=testcb6019b7f8e4b4b1baeb044b072c5e915 Blob=testb63b649aca6764f039677b52ca75e459c
2019-12-18T03:05:04.023Z 4924342c-6234-433f-86df-ad99296838ac verbose: DispatchMiddleware: Dispatching request...
2019-12-18T03:05:04.025Z 4924342c-6234-433f-86df-ad99296838ac info: DispatchMiddleware: Operation=Blob_SetMetadata
2019-12-18T03:05:04.026Z 4924342c-6234-433f-86df-ad99296838ac verbose: AuthenticationMiddlewareFactory:createAuthenticationMiddleware() Validating authentications.
2019-12-18T03:05:04.026Z 4924342c-6234-433f-86df-ad99296838ac info: PublicAccessAuthenticator:validate() Start validation against public access.
2019-12-18T03:05:04.027Z 4924342c-6234-433f-86df-ad99296838ac debug: PublicAccessAuthenticator:validate() Getting account properties...
2019-12-18T03:05:04.027Z 4924342c-6234-433f-86df-ad99296838ac debug: PublicAccessAuthenticator:validate() Retrieved account name from context: devstoreaccount1, container: testcb6019b7f8e4b4b1baeb044b072c5e915, blob: testb63b649aca6764f039677b52ca75e459c
2019-12-18T03:05:04.033Z 4924342c-6234-433f-86df-ad99296838ac debug: PublicAccessAuthenticator:validate() Skip public access authentication. Cannot get public access type for container testcb6019b7f8e4b4b1baeb044b072c5e915
2019-12-18T03:05:04.033Z 4924342c-6234-433f-86df-ad99296838ac info: BlobSharedKeyAuthenticator:validate() Start validation against account shared key authentication.
2019-12-18T03:05:04.034Z 4924342c-6234-433f-86df-ad99296838ac info: BlobSharedKeyAuthenticator:validate() [STRING TO SIGN]:"PUT\n\n\n\n\n\n\n\n\n\n\n\nx-ms-client-request-id:9a3ffec7-23e5-45f9-9716-75749ee73d30\nx-ms-date:Wed, 18 Dec 2019 03:05:04 GMT\nx-ms-meta-key1:value1, \nx-ms-version:2019-02-02\n/devstoreaccount1/devstoreaccount1/testcb6019b7f8e4b4b1baeb044b072c5e915/testb63b649aca6764f039677b52ca75e459c\ncomp:metadata"
2019-12-18T03:05:04.034Z 4924342c-6234-433f-86df-ad99296838ac info: BlobSharedKeyAuthenticator:validate() Calculated authentication header based on key1: SharedKey devstoreaccount1:npLSWTGh4RIIlLC6cNf2u5SqkZG6VBbThPBZm8nzh1s=
2019-12-18T03:05:04.034Z 4924342c-6234-433f-86df-ad99296838ac info: BlobSharedKeyAuthenticator:validate() Validation failed.
2019-12-18T03:05:04.035Z 4924342c-6234-433f-86df-ad99296838ac info: AccountSASAuthenticator:validate() Start validation against account Shared Access Signature pattern.
2019-12-18T03:05:04.035Z 4924342c-6234-433f-86df-ad99296838ac debug: AccountSASAuthenticator:validate() Getting account properties...
2019-12-18T03:05:04.035Z 4924342c-6234-433f-86df-ad99296838ac debug: AccountSASAuthenticator:validate() Retrieved account name from context: devstoreaccount1, container: testcb6019b7f8e4b4b1baeb044b072c5e915, blob: testb63b649aca6764f039677b52ca75e459c
2019-12-18T03:05:04.035Z 4924342c-6234-433f-86df-ad99296838ac debug: AccountSASAuthenticator:validate() Got account properties successfully.
2019-12-18T03:05:04.036Z 4924342c-6234-433f-86df-ad99296838ac debug: AccountSASAuthenticator:validate() Retrieved signature from URL parameter sig: undefined
2019-12-18T03:05:04.036Z 4924342c-6234-433f-86df-ad99296838ac info: AccountSASAuthenticator:validate() Failed to get valid account SAS values from request.
2019-12-18T03:05:04.037Z 4924342c-6234-433f-86df-ad99296838ac info: BlobSASAuthenticator:validate() Start validation against blob service Shared Access Signature pattern.
2019-12-18T03:05:04.037Z 4924342c-6234-433f-86df-ad99296838ac debug: BlobSASAuthenticator:validate() Getting account properties...
2019-12-18T03:05:04.037Z 4924342c-6234-433f-86df-ad99296838ac debug: BlobSASAuthenticator:validate() Retrieved account name from context: devstoreaccount1, container: testcb6019b7f8e4b4b1baeb044b072c5e915, blob: testb63b649aca6764f039677b52ca75e459c
2019-12-18T03:05:04.037Z 4924342c-6234-433f-86df-ad99296838ac debug: BlobSASAuthenticator:validate() Got account properties successfully.
2019-12-18T03:05:04.037Z 4924342c-6234-433f-86df-ad99296838ac debug: BlobSASAuthenticator:validate() Retrieved signature from URL parameter sig: undefined
2019-12-18T03:05:04.038Z 4924342c-6234-433f-86df-ad99296838ac debug: BlobSASAuthenticator:validate() No signature found in request. Skip blob service SAS validation.
2019-12-18T03:05:04.039Z 4924342c-6234-433f-86df-ad99296838ac error: ErrorMiddleware: Received a MiddlewareError, fill error information to HTTP response
2019-12-18T03:05:04.040Z 4924342c-6234-433f-86df-ad99296838ac error: ErrorMiddleware: ErrorName=StorageError ErrorMessage=Server failed to authenticate the request. Make sure the value of the Authorization header is formed correctly including the signature. ErrorHTTPStatusCode=403 ErrorHTTPStatusMessage=Server failed to authenticate the request. Make sure the value of the Authorization header is formed correctly including the signature. ErrorHTTPHeaders={"x-ms-error-code":"AuthorizationFailure","x-ms-request-id":"4924342c-6234-433f-86df-ad99296838ac"} ErrorHTTPBody="\n\n AuthorizationFailure\n Server failed to authenticate the request. Make sure the value of the Authorization header is formed correctly including the signature.\nRequestId:4924342c-6234-433f-86df-ad99296838ac\nTime:2019-12-18T03:05:04.038Z\n" ErrorStack="StorageError: Server failed to authenticate the request. Make sure the value of the Authorization header is formed correctly including the signature.\n at Function.getAuthorizationFailure (C:\\code\\azurite\\src\\blob\\errors\\StorageErrorFactory.ts:253:12)\n at authenticate.then.pass (C:\\code\\azurite\\src\\blob\\authentication\\AuthenticationMiddlewareFactory.ts:25:35)\n at process._tickCallback (internal/process/next_tick.js:68:7)"
2019-12-18T03:05:04.041Z 4924342c-6234-433f-86df-ad99296838ac error: ErrorMiddleware: Set HTTP code: 403
2019-12-18T03:05:04.041Z 4924342c-6234-433f-86df-ad99296838ac error: ErrorMiddleware: Set HTTP status message: Server failed to authenticate the request. Make sure the value of the Authorization header is formed correctly including the signature.
2019-12-18T03:05:04.041Z 4924342c-6234-433f-86df-ad99296838ac error: ErrorMiddleware: Set HTTP Header: x-ms-error-code=AuthorizationFailure
2019-12-18T03:05:04.042Z 4924342c-6234-433f-86df-ad99296838ac error: ErrorMiddleware: Set HTTP Header: x-ms-request-id=4924342c-6234-433f-86df-ad99296838ac
2019-12-18T03:05:04.042Z 4924342c-6234-433f-86df-ad99296838ac error: ErrorMiddleware: Set content type: application/xml
2019-12-18T03:05:04.042Z 4924342c-6234-433f-86df-ad99296838ac error: ErrorMiddleware: Set HTTP body: "\n\n AuthorizationFailure\n Server failed to authenticate the request. Make sure the value of the Authorization header is formed correctly including the signature.\nRequestId:4924342c-6234-433f-86df-ad99296838ac\nTime:2019-12-18T03:05:04.038Z\n"
2019-12-18T03:05:04.043Z 4924342c-6234-433f-86df-ad99296838ac info: EndMiddleware: End response. TotalTimeInMS=21 StatusCode=403 StatusMessage=Server failed to authenticate the request. Make sure the value of the Authorization header is formed correctly including the signature. Headers={"server":"Azurite-Blob/3.3.0-preview","x-ms-error-code":"AuthorizationFailure","x-ms-request-id":"4924342c-6234-433f-86df-ad99296838ac","content-type":"application/xml"}

```

Test Case:
```
Test Name: CloudPageBlobGetEmptyMetadata
Test FullName: Microsoft.Azure.Storage.Blob.CloudPageBlobTest.CloudPageBlobGetEmptyMetadata
Test Source: C:\code\azure-storage-net\Test\ClassLibraryCommon\Blob\CloudPageBlobTest.cs : line 1523
Test Outcome: Failed
Test Duration: 0:00:00.3238956

Result StackTrace:
at Microsoft.Azure.Storage.Core.Executor.Executor.ExecuteAsync[T](RESTCommand`1 cmd, IRetryPolicy policy, OperationContext operationContext, CancellationToken token) in C:\code\azure-storage-net\Lib\ClassLibraryCommon\Core\Executor\Executor.cs:line 274
at Microsoft.Azure.Storage.Core.Executor.Executor.<>c__DisplayClass0_0`1.b__0() in C:\code\azure-storage-net\Lib\ClassLibraryCommon\Core\Executor\Executor.cs:line 41
at Microsoft.Azure.Storage.Core.Util.CommonUtility.RunWithoutSynchronizationContext[T](Func`1 actionToRun) in C:\code\azure-storage-net\Lib\Common\Core\Util\CommonUtility.cs:line 378
at Microsoft.Azure.Storage.Core.Executor.Executor.ExecuteSync[T](RESTCommand`1 cmd, IRetryPolicy policy, OperationContext operationContext) in C:\code\azure-storage-net\Lib\ClassLibraryCommon\Core\Executor\Executor.cs:line 40
at Microsoft.Azure.Storage.Blob.CloudBlob.SetMetadata(AccessCondition accessCondition, BlobRequestOptions options, OperationContext operationContext) in C:\code\azure-storage-net\Lib\ClassLibraryCommon\Blob\CloudBlob.cs:line 1658
at Microsoft.Azure.Storage.Blob.CloudPageBlobTest.CloudPageBlobGetEmptyMetadata() in C:\code\azure-storage-net\Test\ClassLibraryCommon\Blob\CloudPageBlobTest.cs:line 1542
Result Message:
Test method Microsoft.Azure.Storage.Blob.CloudPageBlobTest.CloudPageBlobGetEmptyMetadata threw exception:
Microsoft.Azure.Storage.StorageException: Server failed to authenticate the request. Make sure the value of the Authorization header is formed correctly including the signature.

```