feat: upgrade lance-namespace to 0.4.5

[jackye1995]

1. Also use Default:default() for constructing request and response models so that we don't need to make change to the struct inputs every time we add new things.
2. Leverage newly added identity to cache vended credentials
3. Support newly added load_detailed_metadata and vend_credentials flags in requests

[github-actions]

Code Review

Summary: This PR upgrades lance-namespace from 0.4.0 to 0.4.3 and refactors request/response struct construction to use ..Default::default() for better forward compatibility.

Assessment: LGTM

No P0/P1 issues found. The changes are straightforward and improve maintainability.

The ..Default::default() pattern is a good practice that reduces churn when new optional fields are added to the namespace API structs.

Minor note: The #[allow(clippy::needless_update)] annotations in dir.rs:831 and manifest.rs:1371/1383 are correctly placed to suppress warnings when ..Default::default() is used on structs that currently have no additional fields - this is intentional for forward compatibility.

[codecov]

Codecov Report

❌ Patch coverage is 25.02058% with 911 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ust/lance-namespace-impls/src/credentials/azure.rs	0.73%	403 Missing ⚠️
rust/lance-namespace-impls/src/credentials/aws.rs	0.99%	199 Missing ⚠️
rust/lance-namespace-impls/src/credentials/gcp.rs	8.54%	182 Missing ⚠️
rust/lance-namespace-impls/src/rest_adapter.rs	55.80%	76 Missing and 4 partials ⚠️
...ust/lance-namespace-impls/src/credentials/cache.rs	84.65%	29 Missing ⚠️
rust/lance-namespace-impls/src/credentials.rs	0.00%	14 Missing ⚠️
rust/lance-namespace-impls/src/dir.rs	86.66%	2 Missing ⚠️
rust/lance/src/dataset.rs	66.66%	1 Missing ⚠️
rust/lance/src/dataset/builder.rs	0.00%	1 Missing ⚠️

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