opengl: egl: Can't handle configless egl contexts

GTK4's egl setup was recently rewritten to use configless EGL contexts when available.

I've just updated my system to F35, getting a newer gstreamer stack (1.19.2), and now video playback in widget-factory is broken. I get errors from gstreamers gl setup code:

1467:gst_gl_context_egl_fill_info:<glwrappedcontext0> could not retrieve egl config from its ID 0x0. Wrong EGLDisplay or context?

Disabling the configless EGL contexts on the gtk side makes video playback work again.

So I think gstreamers gl setup code needs to learn about EGL_KHR_no_config_context