Remove Built-in sum and Rename to lowercase `sum` #27662

Job	Run time
cargo check	3m 23s
Check cargo fmt	28s
build with wasm-pack	2m 3s
cargo test (macos)	9m 5s
cargo test (macos-aarch64)	8m 56s
Verify MSRV (Min Supported Rust Version)	6m 17s
Verify Vendored Code	44s
cargo test (win64)	33m 59s
cargo test (amd64)	9m 5s
cargo examples (amd64)	12m 1s
cargo test datafusion-cli (amd64)	3m 40s
check Cargo.toml formatting	2m 51s
clippy	4m 57s
check configs.md is up-to-date	2m 19s
cargo test hash collisions (amd64)	8m 33s
cargo doc	3m 22s
Run sqllogictest with Postgres runner	3m 10s
cargo test doc (amd64)	12m 3s
cargo test pyarrow (amd64)	2m 41s
verify benchmark results (amd64)	10m 13s
	2h 19m 50s

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