The Qt backend directly calls some OpenGL functions (glClear, glHint,
glViewport), but since OCV 4.5.5 the GL libraries are no longer part
of the global extra dependencies. When linking with "-Wl,--no-undefined"
this causes linker errors:

`opencv-4.5.5/modules/highgui/src/window_QT.cpp:3307: undefined reference to `glClear'`

Fixes: #21346
Related issues: #21299