cuda.core: keep the mipmap/LOD example in the texture/surface PR

MipmappedArray is a headline type of this PR but was only exercised by unit
tests after the example split. Pull gl_interop_mipmap_lod.py back in so the
mipmap pyramid + get_level + trilinear (LINEAR mipmap) sampling with LOD bias
path has an end-to-end demonstration; re-wire it in the example-test
requirements map (has_display-gated). The other gl_interop_*.py demos stay on
feature/cuda-core-texture-examples-467 for the follow-up examples PR.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: rparolin