Remove get_scan_files and ExecutionPlan::file_scan_config (#7357) #18293

Job	Run time
Check cargo fmt	59s
cargo check	7m 31s
cargo test (mac)	25m 4s
Verify Vendored Code	1m 0s
Verify MSRV	10m 13s
cargo test (win64)	31m 37s
cargo test doc (amd64)	18m 47s
cargo examples (amd64)	8m 33s
cargo test (amd64)	20m 19s
cargo test datafusion-cli (amd64)	5m 29s
check Cargo.toml formatting	1m 54s
clippy	6m 44s
check configs.md is up-to-date	3m 29s
cargo test hash collisions (amd64)	26m 3s
cargo doc	5m 44s
Run sqllogictest with Postgres runner	5m 42s
cargo test pyarrow (amd64)	3m 19s
verify benchmark results (amd64)	36m 26s
	3h 38m 53s

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