Fix nightly macOS clippy-features job by removing stale workspace feature

[Copilot]

The nightly clippy-features (macos) job was failing because the workflow passed bf_tree in --features, but no selected workspace package exposes that feature. This PR removes the stale feature from the nightly feature set so clippy can run against valid workspace features.

• Root cause

  • .github/workflows/nightly.yml defined DISKANN_FEATURES with bf_tree, which is not a valid workspace feature name for the clippy workspace invocation.

• Change

  • Updated the nightly workflow environment feature list to remove bf_tree and keep only valid features used by the workspace clippy/test jobs.

• Patch excerpt

  # .github/workflows/nightly.yml
  DISKANN_FEATURES: "virtual_storage,spherical-quantization,product-quantization,tracing,experimental_diversity_search,disk-index,flatbuffers,linalg,codegen"

[arrayka]

It's a duplicate of #1112