fix: open additional storage options provider related apis in lance dataset

[jackye1995]

related to lancedb/lancedb#2969

[github-actions]

Code Review

P1 - Missing Test Coverage

The PR adds two new public APIs without tests:

1. The storage_options_provider parameter for lance.dataset()
2. The new_file_session() method on LanceDataset

Per the project guidelines, code without tests should not be merged. Please add tests that verify:

• A custom storage_options_provider takes precedence over namespace-created provider
• new_file_session() correctly inherits the provider and storage options

P1 - Serialization Concern

LanceDataset uses __reduce__ for pickling (lines 488-499) but _storage_options_provider is not included in the serialization. This means after deserialization:

• latest_storage_options() won't be able to refresh credentials (relies on Rust-side provider)
• new_file_session() will create sessions without a provider (_storage_options_provider will be None)

If this is intentional (providers can't be serialized), it should be documented. If not, consider how deserialized datasets should handle credential refresh.

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The implementation itself looks correct - precedence logic in __init__.py and the new_file_session() factory method properly delegate to existing infrastructure.