Minor: Simplify `IdentTaker` #35493

Job	Run time
Check License Header	2m 15s
cargo check	12m 34s
build with wasm-pack	3m 23s
cargo test (macos)	13m 53s
cargo test (win64)	1h 12m 57s
Check cargo fmt	42s
cargo test (macos-aarch64)	12m 36s
Verify MSRV (Min Supported Rust Version)	9m 17s
Verify Vendored Code	55s
cargo test datafusion-cli (amd64)	4m 36s
cargo doc	4m 18s
cargo examples (amd64)	14m 38s
cargo test (amd64)	12m 13s
cargo test doc (amd64)	17m 7s
Run sqllogictest with Postgres runner	4m 21s
verify benchmark results (amd64)	14m 18s
check Cargo.toml formatting	2m 51s
clippy	7m 28s
check configs.md and ***_functions.md is up-to-date	3m 49s
cargo test hash collisions (amd64)	28m 11s
cargo test pyarrow (amd64)	3m 10s
	4h 5m 32s

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