Correct the eglQueryWaylandBufferWL_func prototype

I am trying to build against a Qt built without OpenGL. In that case, the
openGL headers have not been included and therefore GLboolean is not
defined. Use EGLBoolean to match the EGL prototype.

See also https://invent.kde.org/frameworks/kwayland/-/commit/d18486c03346ce7b120ed299bafb67b2ad9ef22f