Allow to find fonts for screenshot tests #1846

Job	Run time
cmake-build (Windows - MSVC 2022, windows-latest, Debug, cl, cl, Visual Studio 17 2022, -DIGL_WIT...	7m 55s
cmake-build (Windows - MSVC 2022 (no OpenGL), windows-latest, Debug, cl, cl, Visual Studio 17 202...	6m 12s
Android (Ubuntu)	9m 51s
cmake-build (Ubuntu - Clang, ubuntu-latest, Debug, clang, clang++, Unix Makefiles, -DIGL_WITH_TRA...	7m 21s
cmake-build (Ubuntu - GCC, ubuntu-latest, Debug, gcc, g++, Unix Makefiles, -DIGL_WITH_TRACY=ON -D...	5m 22s
cmake-build (macOS - Clang (Xcode), macos-latest, Debug, clang, clang++, Xcode, -DIGL_WITH_VULKAN...	47m 4s
cmake-build (macOS - Clang (Unix Makefiles), macos-latest, Debug, clang, clang++, Unix Makefiles,...	1h 9m 52s
	2h 33m 37s

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