Consider increasing language version from C++14.

**Is your feature request related to a problem? Please describe.**
Dependencies like wil no longer officially support C++14, and have made changes that require newer language versions. (https://github.com/microsoft/wil/pull/615#issuecomment-3861930274)

**Describe the solution you'd like**
Azure SDK libraries – at least those depending on `wil`, namely `azure-core-cpp` and `azure-identity-cpp`, target a newer C++ language version, such as C++17.

**Describe alternatives you've considered**
Pin to older wil versions, which is what we do in conda-forge.

**Additional context**
Add any other context or screenshots about the feature request here.

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