Nullable::Emplace doesn't set m_hasValue = true

[tudor]

Describe the bug
Azure::Nullable::Emplace creates an object as m_value but forgets to set m_hasValue = true.

Code Snippet

Azure::Nullable<int> x;
x.Emplace(42);
assert(x.HasValue());

Expected behavior
Emplace should actually engage the Nullable object, just like std::optional::emplace.

Setup (please complete the following information):
The bug still exists in trunk at the time of my writing:

azure-sdk-for-cpp/sdk/core/azure-core/inc/azure/core/nullable.hpp

Line 220 in 1b2e58f

::new (static_cast<void*>(&m_value)) T(std::forward<U>(Args)...);