refactor(chain)!: update `TopologicalIter` to take an iterator #299

Job	Run time
prepare	4s
Rust fmt	17s
Check WASM	1m 13s
Check no_std	44s
Build & Test (1.88.0, true, --all-features)	3m 45s
Build & Test (1.75.0, --no-default-features --features miniscript/no-std,bdk_chain/hashbrown)	2m 29s
Rust clippy	47s
Build & Test (1.63.0, --no-default-features --features miniscript/no-std,bdk_chain/hashbrown)	10m 0s
Build & Test Examples (example_cli)	39s
Build & Test (1.88.0, true, --no-default-features --features miniscript/no-std,bdk_chain/hashbrown)	2m 10s
Build & Test Examples (example_esplora)	58s
Build & Test Examples (example_bitcoind_rpc_polling)	45s
Build & Test (1.75.0, --all-features)	3m 59s
Build & Test (1.63.0, --all-features)	10m 51s
Build & Test Examples (example_electrum)	58s
	39m 39s

Provide feedback