[red-knot] Handle possibly-unbound instance members #41172

Job	Run time
Determine changes	13s
cargo build (release)	0s
cargo fmt	23s
mkdocs	2m 30s
pre-commit	3m 14s
python package	1m 17s
cargo clippy	1m 54s
cargo test (linux)	2m 2s
cargo test (linux, release)	4m 34s
cargo test (windows)	3m 39s
cargo build (msrv)	2m 4s
cargo shear	23s
cargo fuzz build	4m 11s
cargo test (wasm)	1m 44s
test scripts	1m 10s
benchmarks	4m 15s
formatter instabilities and black similarity	0s
ecosystem	20s
test ruff-lsp	34s
fuzz parser	0s
	34m 27s

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