[Chronik] Fix `CARGO_BUILD_DIR`, incorrectly based on CMAKE_CURRENT_BINARY_DIR instead of CMAKE_BINARY_DIR
[Chronik] Fix `CARGO_BUILD_DIR`, incorrectly based on CMAKE_CURRENT_BINARY_DIR instead of CMAKE_BINARY_DIR

Summary:
CARGO_BUILD_DIR is the path where the cxx crate generates the bridging sources.
We've incorrectly used CMAKE_CURRENT_BINARY_DIR instead of CMAKE_BINARY_DIR, and this fixes it.

Test Plan: `ninja check-crates`

Reviewers: Fabien, #bitcoin_abc

Reviewed By: Fabien, #bitcoin_abc

Differential Revision: https://reviews.bitcoinabc.org/D11862

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