Remove `petgraph` from `bevy_ecs` #53251

Job	Run time
ci	4m 40s
build (windows-latest)	9m 52s
build (ubuntu-latest)	4m 28s
miri	11m 27s
build (macos-latest)	4m 15s
toml	2m 6s
typos	5s
check-bevy-internal-imports	4s
check-missing-examples-in-docs	30s
check-doc	9m 41s
run-examples-macos-metal	5m 49s
check-missing-features-in-docs	33s
markdownlint	1m 4s
check-compiles	7m 11s
check-compiles-no-std	54s
build-wasm-atomics	2m 1s
msrv	1m 52s
build-wasm	1m 51s
	1h 8m 23s

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