Use `TxIn` type from bitcoin-ffi #1037

Job	Run time
Build and test macOS arm64 wheels (3.8)	4m 4s
Build and test macOS x86_64 wheels (3.8)	5m 5s
Build and test macOS x86_64 wheels (3.9)	5m 49s
Build and test macOS arm64 wheels (3.9)	6m 10s
Build and test macOS x86_64 wheels (3.10)	5m 6s
Build and test macOS arm64 wheels (3.10)	6m 6s
Build and test Manylinux 2.28 x86_64 wheels (cp38-cp38)	3m 47s
Build and test macOS x86_64 wheels (3.11)	6m 15s
Build and test Manylinux 2.28 x86_64 wheels (cp39-cp39)	3m 49s
Build and test macOS arm64 wheels (3.11)	4m 33s
Build and test Windows wheels (3.8)	5m 56s
Build and test macOS x86_64 wheels (3.12)	4m 6s
Build and test Manylinux 2.28 x86_64 wheels (cp310-cp310)	3m 40s
Build and test Windows wheels (3.9)	6m 7s
Build and test macOS arm64 wheels (3.12)	6m 3s
Build and test Manylinux 2.28 x86_64 wheels (cp311-cp311)	3m 45s
Build and test Windows wheels (3.10)	5m 40s
Build and test Manylinux 2.28 x86_64 wheels (cp312-cp312)	3m 47s
Build and test Windows wheels (3.11)	5m 35s
Build and test Windows wheels (3.12)	5m 45s
	1h 41m 8s

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