when building steamaudio as static, the symbols get exported.

[brightening-eyes]

System Information
Please provide the following information about your system:

• Steam Audio version: latest from git repository
• (If applicable) Unity version: n/a
• (If applicable) Unreal Engine version: n/a
• (If applicable) FMOD Studio version: n/a
• Operating System and version: windows 11 (although this is true in other operating systems)
• (Optional) CPU architecture (e.g. x86-64, armv7): this issue is cpu independent, but mine is x64

Issue Description
no matter the type of build (static/dynamic library), in phonon.h when building steamaudio, the symbols get exported: phonon.h lines 30 to 39

Steps To Reproduce
build steamaudio with msvc and set BUILD_SHARED_LIBS to false and compile the test project. then the symbols get exported into the executable.

Crash Dump
n/a