chore!: change ec_add to unsafe implementation (but much better perf)

[ludamad]

Reverts the revert #8722

original description:
Use unconditional_add for ec_add ACIR opcode.
This improves a lot the performance of the opcode, but also makes it unsafe.
I keep the PR as draft until aztec packages are sync with Noir PR noir-lang/noir#5858 which adds the checks in the stdlib function.
The unsafe version can then be used when we know the inputs are valid (for instance if they come from a previous add).
n.b.: the real performance boost will happen when we will be able to use the unsafe version.

[github-actions]

Changes to circuit sizes

Generated at commit: 4830e1d0452df21f3018864b24d7aae56a38d55d, compared to commit: 80acfd943ac3cd42b548043824f530018ac07a2d

🧾 Summary (100% most significant diffs)

Program	ACIR opcodes (+/-)	%	Circuit size (+/-)	%
private_kernel_reset_tiny	0 ➖	0.00%	-4 ✅	-0.01%
private_kernel_reset_small	0 ➖	0.00%	-8 ✅	-0.01%
private_kernel_reset_medium	0 ➖	0.00%	-16 ✅	-0.01%
private_kernel_reset_big	0 ➖	0.00%	-32 ✅	-0.01%
private_kernel_reset	0 ➖	0.00%	-64 ✅	-0.01%
private_kernel_reset_full_inner	0 ➖	0.00%	-64 ✅	-0.01%

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Full diff report 👇

Program	ACIR opcodes (+/-)	%	Circuit size (+/-)	%
private_kernel_reset_tiny	35,560 (0)	0.00%	76,374 (-4)	-0.01%
private_kernel_reset_small	39,387 (0)	0.00%	102,743 (-8)	-0.01%
private_kernel_reset_medium	47,044 (0)	0.00%	155,660 (-16)	-0.01%
private_kernel_reset_big	62,353 (0)	0.00%	261,697 (-32)	-0.01%
private_kernel_reset	92,596 (0)	0.00%	472,771 (-64)	-0.01%
private_kernel_reset_full_inner	85,690 (0)	0.00%	443,083 (-64)	-0.01%