This library deliberately links PUBLICly against Qt6::Widgets and
Qt6::OpenGL. Same for the target_include_directories call.
This partially reverts a5de12f0d7.
This fixes the builds of examples using this library.
Change-Id: I2b5791044afc82e71df4a3bbfc26e5b1ab9afa76
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>