[red-knot] Add test for nested attribute access #39388

Job	Run time
Determine changes	8s
cargo fmt	19s
mkdocs	2m 32s
cargo build (release)	0s
pre-commit	3m 12s
python package	1m 24s
cargo clippy	1m 52s
cargo test (linux)	1m 46s
cargo test (linux, release)	3m 59s
cargo build (msrv)	4m 13s
cargo fuzz build	4m 59s
cargo test (wasm)	1m 45s
cargo test (windows)	4m 18s
benchmarks	4m 55s
test scripts	1m 6s
cargo shear	22s
formatter instabilities and black similarity	0s
test ruff-lsp	40s
ecosystem	2m 38s
fuzz parser	0s
	40m 8s

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