Feat: enable setting the auth emulator in code

[AustinBenoit]

Description

Provide details of the change, and generalize the change in the PR title above.

Feat: enable setting the auth emulator in code

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Testing

Describe how you've tested these changes.

Ran locally with emulator in desktop.

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Type of Change

Place an x the applicable box:

• Bug fix. Add the issue # below if applicable.
• New feature. A non-breaking change which adds functionality.
• Other, such as a build process or documentation change.

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[gemini-code-assist]

Code Review

This pull request exposes the UseEmulator method in the SWIG interface for the Auth SDK and adds commented-out usage examples in the test app. The reviewer identified a potential crash if a null pointer is passed as the host parameter and suggested adding a null check to handle this safely.

[gemini-code-assist]

If host is nullptr (for example, if a C# user passes null to UseEmulator), passing it directly to self->UseEmulator will cause undefined behavior or a crash when constructing std::string implicitly from a null pointer on the C++ side.

We should add a null check for host to prevent potential crashes and ensure defensive programming.

  void UseEmulator(const char* host, int port) {
    if (host != nullptr) {
      self->UseEmulator(host, port);
    }
  }