Find a better way to wait until config comes into effect rather than just sleep

[Jinming-Hu]

azure-sdk-for-cpp/sdk/storage/azure-storage-files-datalake/test/datalake_file_client_test.cpp

Line 574 in 414a576

std::this_thread::sleep_for(std::chrono::seconds(30));

[ahsonkhan]

The same issue applies for these other datalake tests that also use SetAccessPolicy:

azure-sdk-for-cpp/sdk/storage/azure-storage-files-datalake/test/datalake_directory_client_test.cpp

Lines 375 to 385 in 8f03807

	containerClient.SetAccessPolicy(options);
	auto directoryClient
	= Azure::Storage::Files::DataLake::DirectoryClient::CreateFromConnectionString(
	AdlsGen2ConnectionString(), m_fileSystemName, objectName);
	EXPECT_NO_THROW(directoryClient.Create());
	auto anonymousClient
	= Azure::Storage::Files::DataLake::DirectoryClient(directoryClient.GetUri());
	EXPECT_NO_THROW(anonymousClient.GetProperties());

azure-sdk-for-cpp/sdk/storage/azure-storage-files-datalake/test/datalake_path_client_test.cpp

Lines 328 to 336 in 8f03807

	containerClient.SetAccessPolicy(options);
	auto pathClient = Azure::Storage::Files::DataLake::PathClient::CreateFromConnectionString(
	AdlsGen2ConnectionString(), m_fileSystemName, objectName);
	EXPECT_NO_THROW(pathClient.Create(Files::DataLake::Models::PathResourceType::File));
	auto anonymousClient = Azure::Storage::Files::DataLake::PathClient(pathClient.GetUri());
	EXPECT_NO_THROW(anonymousClient.GetProperties());