fix: correct signed integer handling in `noirc_abi` #15777

Job	Run time
build-nargo	2m 30s
build-noirc-abi	1m 27s
build-noir-wasm	3m 48s
build-acvm-js	1m 31s
noirc_abi	1m 19s
ACVM JS (Node.js)	41s
ACVM JS (Browser)	1m 16s
Example scripts	12s
noir_codegen	1m 15s
Noir JS	1m 3s
Check external repo - ${{ matrix.project.repo }}	0s
noir_wasm	1m 59s
Integration Tests (Browser)	1m 51s
Integration Tests (Node)	2m 15s
End	1s
	21m 8s

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