Update optimum-et pin in ET CI

[metascroy]

As titled

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/12866

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❌ 1 New Failure, 8 Cancelled Jobs, 1 Unrelated Failure

As of commit 005460d with merge base de89397 ():

NEW FAILURE - The following job has failed:

• pull / test-llava-runner-linux / linux-job (gh)
  RuntimeError: Command docker exec -t cc78912bc88969a955bbd9fa174bda42a7f3731ca58249e620f4fa568167f0f1 /exec failed with exit code 139

CANCELLED JOBS - The following jobs were cancelled. Please retry:

• android-perf / export-models (Qwen/Qwen3-0.6B, et_xnnpack_custom_spda_kv_cache_8da4w, samsung_galaxy_s22, arn:aw... / linux-job (gh)
• android-perf / export-models (Qwen/Qwen3-0.6B, hf_xnnpack_custom_spda_kv_cache_8da4w, samsung_galaxy_s22, arn:aw... / linux-job (gh)
  ##[error]The operation was canceled.
• pull / test-models-linux (ic4, portable, linux.4xlarge.memory) / linux-job (gh)
  ##[error]The operation was canceled.
• pull / test-models-linux (phi_4_mini, portable, linux.4xlarge.memory) / linux-job (gh)
  ##[error]The operation was canceled.
• pull / unittest-arm-backend-with-no-fvp (test_pytest_models) / linux-job (gh)
  ##[error]The operation was canceled.
• trunk / test-demo-backend-delegation (buck2) / linux-job (gh)
  ##[error]The operation was canceled.
• trunk / test-demo-backend-delegation (cmake) / linux-job (gh)
  ##[error]The operation was canceled.
• trunk / test-models-linux-aarch64 (ic4, portable, linux.arm64.2xlarge) / linux-job (gh)
  ##[error]The operation was canceled.

BROKEN TRUNK - The following job failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / test-phi-3-mini-runner-linux / linux-job (gh) (trunk failure)
  AttributeError: 'StaticCacheConfig' object has no attribute 'get'

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[guangy10]

LGTM