OpenGL interop should supply the texture format to the sampler

The swizzle configuration for texture sampling is decided in sampler.c depending on whether GL_ARB_texture_rg is available or not. However, interop might not follow the format that is expected in this test.

In particular, vaapi interop is using GL_EGL_image extension and call EGLImageTargetTexture2DOES to assign the EGL image, which will change the internal format and use a format like GL_RG instead for NV12. Since after GL 3.0, GL_RG is core, there is no extension for it and we use the wrong code path, leading to #26735 (closed).

Instead, the sampler should use a texture configuration from the interop, and the checks should be moved to where the textures are actually created, for instance when using interop_sw.

In addition, after being moved, the checks should favor GL_RG when OpenGL >= 3.0 is used, and check https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_texture_rg.txt on OpenGL ES too.

interop_cvpx is already doing some code like this to handle BGRA and UYVY CVPX chroma.