Implement Utf8View for lpad scalar function #30599

Job	Run time
cargo check	5m 26s
build with wasm-pack	2m 13s
cargo test (macos)	9m 35s
cargo test (win64)	41m 18s
Check cargo fmt	27s
cargo test (macos-aarch64)	9m 39s
Verify MSRV (Min Supported Rust Version)	6m 22s
Verify Vendored Code	1m 14s
cargo test datafusion-cli (amd64)	3m 50s
cargo test (amd64)	9m 22s
clippy	5m 23s
check Cargo.toml formatting	2m 58s
cargo test hash collisions (amd64)	13m 48s
cargo doc	3m 38s
cargo test doc (amd64)	14m 2s
cargo examples (amd64)	13m 9s
Run sqllogictest with Postgres runner	3m 13s
cargo test pyarrow (amd64)	2m 54s
verify benchmark results (amd64)	11m 50s
check configs.md is up-to-date	2m 39s
	2h 43m 0s

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