fix: remove redundant references in format macro arguments to satisfy clippy

[andygrove]

Which issue does this PR close?

N/A. This is a small lint fix to unblock CI.

Rationale for this change

A newer Rust/clippy version now flags the useless_borrows_in_formatting lint (redundant reference in ... argument) in two workspace crates. CI runs cargo clippy --all-targets --workspace -- -D warnings, and clippy aborts each crate at its first denied lint, so the two occurrences surface one at a time: fixing only the first lets clippy proceed to the next crate and fail there.

error: redundant reference in `info!` argument
   --> fs-hdfs/src/hdfs.rs:103:54

error: redundant reference in `write!` argument
   --> spark-expr/src/conversion_funcs/cast.rs:735:69

The fs-hdfs crate is a workspace member listed in members but not default-members, so local default-member builds do not lint it, which is why this only shows up in CI.

What changes are included in this PR?

Remove the redundant & in two format macro arguments:

• native/fs-hdfs/src/hdfs.rs:103: the namenode_uri argument in the info! call.
• native/spark-expr/src/conversion_funcs/cast.rs:735: the eval_mode argument in the Cast Display write! call.

How are these changes tested?

cargo clippy --all-targets --workspace -- -D warnings passes end-to-end with these changes and fails without them. Covered by the existing rust-test CI job.

[mbutrovich]

#4840 has the fixes already and should get through CI first.