chore(deps): upgrade object_store to 0.14.1

[Xuanwo]

Which issue does this PR close?

N/A.

Rationale for this change

object_store_opendal should track the object_store 0.14 release. The new release adds implementation-specific extensions to its result types. DataFusion 54 still depends on object_store 0.13, so its example cannot compile once the adapter moves to 0.14.

What changes are included in this PR?

• Upgrade object_store from 0.13.1 to 0.14.1.
• Return empty extensions from OpenDAL-backed get, put, multipart, and list results.
• Remove the incompatible DataFusion example and its development dependencies.
• Update the remaining S3 example for the 0.14 extension trait.

Validation:

• cargo clippy --all-targets --all-features -- -D warnings
• cargo test --all-features
• OPENDAL_TEST=memory cargo test behavior
• ./scripts/workspace.py cargo fmt -- --check

Are there any user-facing changes?

Yes. object_store_opendal now implements the object_store 0.14 API, so downstream users must use a compatible 0.14 release. The DataFusion example is removed because DataFusion 54 uses object_store 0.13.

AI Usage Statement

OpenAI Codex (GPT-5) was used to implement and validate this change.