Skip test_cartpole_newton_visualizer_viewergl_rgb_motion in CI

ViewerGL.get_frame returns a fully-black 600x600x3 buffer in CI on the
current Isaac Sim image + Newton 1.2.0rc2 + warp-lang 1.13 cohort. The
failure is deterministic across two consecutive reruns of the same SHA
and reproduces on every recent PR that touches the rendering / camera /
sensor / USD stack:

  #5523 (Newton 1.2.0rc2 bump)
  #5534 (Camera/Renderer warp rewrite)
  #5024 (heterogeneous dexsuite)
  #5495 (usd-core 25.11)
  #5492 (OVRTX rendering tests)

9 visualizer-job failures across these 5 PRs in the last 100 build.yaml
runs, zero failures on PRs outside that scope.

Investigation ruled out:
  * rc1 -> rc2 viewer code diff -- only a 7-line image_logger.clear
    addition.
  * wp.RegisteredGLBuffer API -- byte-identical between warp-lang 1.12
    and 1.13.
  * pure CI flakiness -- deterministic across reruns.
  * the bump cohort alone -- branches on warp-lang 1.12 + Newton @a27277e
    both pass and fail this test depending on PR content.

Strongest remaining hypothesis: a CUDA-OpenGL interop init-order
fragility in the PBO + glReadPixels + RegisteredGLBuffer.map readback
path that gets tipped to deterministic-fail by any source change
perturbing GL/CUDA bring-up. Pinning it down requires py-spy or
glReadPixels return-code inspection inside the CI container, which is
out of scope for this change.

Skip both ['physx', 'newton'] parametrizations until the root cause
is identified. Re-enable in a follow-up PR.

Author: hujc7

source/isaaclab_visualizers/changelog.d/jichuanh-disable-viewergl-flaky.skip

@@ -522,6 +522,22 @@ def test_cartpole_newton_visualizer_tiled_camera_rgb_non_black(
 
 
 @pytest.mark.isaacsim_ci
+@pytest.mark.skip(
+    reason=(
+        "ViewerGL.get_frame returns a fully-black 600x600x3 buffer in CI on the current "
+        "Isaac Sim image + Newton 1.2.0rc2 + warp-lang 1.13 cohort. Failure is "
+        "deterministic across two consecutive reruns of the same SHA and reproduces on "
+        "every PR that touches the rendering / camera / sensor / USD stack (5 PRs hit it "
+        "in the last 100 build.yaml runs); zero failures on PRs outside that scope. "
+        "Investigation ruled out: rc1->rc2 viewer code diff (7-line image_logger.clear "
+        "only), wp.RegisteredGLBuffer API (byte-identical 1.12 vs 1.13), pure flakiness "
+        "(deterministic), and the bump cohort alone (warp-1.12 branches both pass and "
+        "fail). Strongest remaining hypothesis: a CUDA-OpenGL interop init-order "
+        "fragility in the PBO + glReadPixels + RegisteredGLBuffer.map path that gets "
+        "tipped by any source change perturbing GL/CUDA bring-up. Re-enable once root "
+        "cause is identified."
+    )
+)
 @pytest.mark.parametrize("backend_kind", ["physx", "newton"])
 def test_cartpole_newton_visualizer_viewergl_rgb_motion(backend_kind: str, caplog: pytest.LogCaptureFixture) -> None:
     """Newton GL (``ViewerGL.get_frame``): full motion steps, last frame non-black; early vs late differ; logs."""