Use `TxIn` type from bitcoin-ffi #1036

Job	Run time
Build and test macOS arm64 wheels (3.8)	6m 15s
Build and test Windows wheels (3.8)	6m 8s
Build and test macOS x86_64 wheels (3.8)	7m 19s
Build and test macOS arm64 wheels (3.9)	5m 1s
Build and test Windows wheels (3.9)	5m 29s
Build and test Manylinux 2.28 x86_64 wheels (cp38-cp38)	3m 47s
Build and test macOS x86_64 wheels (3.9)	5m 22s
Build and test macOS arm64 wheels (3.10)	5m 42s
Build and test Windows wheels (3.10)	5m 22s
Build and test Manylinux 2.28 x86_64 wheels (cp39-cp39)	3m 42s
Build and test macOS x86_64 wheels (3.10)	7m 28s
Build and test macOS arm64 wheels (3.11)	5m 9s
Build and test Windows wheels (3.11)	5m 21s
Build and test Manylinux 2.28 x86_64 wheels (cp310-cp310)	3m 46s
Build and test macOS x86_64 wheels (3.11)	7m 42s
Build and test macOS arm64 wheels (3.12)	5m 58s
Build and test Windows wheels (3.12)	5m 34s
Build and test Manylinux 2.28 x86_64 wheels (cp311-cp311)	3m 45s
Build and test macOS x86_64 wheels (3.12)	6m 24s
Build and test Manylinux 2.28 x86_64 wheels (cp312-cp312)	3m 44s
	1h 48m 58s

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