chore: remove unnecessary endianness flips when outputting final sha256 hash

[TomAFrench]

…

Description

Problem*

Resolves

Summary*

See AztecProtocol/aztec-packages#9471

Additional Context

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[github-actions]

Changes to Brillig bytecode sizes

Generated at commit: b24e0d44e0649b93280d825b6fba9d94fe768fea, compared to commit: 83d29f259debe41d0b5cdfb6e63d31733ae4e0c7

🧾 Summary (10% most significant diffs)

Program	Brillig opcodes (+/-)	%
brillig_sha256	+13 ❌	+1.68%
regression_4449	+13 ❌	+1.57%
array_dynamic_nested_blackbox_input	+13 ❌	+1.35%

---

Full diff report 👇

Program	Brillig opcodes (+/-)	%
brillig_sha256	785 (+13)	+1.68%
regression_4449	843 (+13)	+1.57%
array_dynamic_nested_blackbox_input	973 (+13)	+1.35%
ecdsa_secp256k1	1,001 (+13)	+1.32%
array_dynamic_blackbox_input	1,150 (+13)	+1.14%
conditional_1	1,296 (+14)	+1.09%
conditional_regression_short_circuit	1,399 (+9)	+0.65%
6	1,830 (+9)	+0.49%
sha2_byte	3,210 (+14)	+0.44%
sha256_var_padding_regression	5,054 (-6)	-0.12%
brillig_cow_regression	2,277 (-4)	-0.18%
sha256_regression	7,081 (-25)	-0.35%
sha256_var_size_regression	1,981 (-9)	-0.45%
ram_blowup_regression	990 (-6)	-0.60%
sha256	1,991 (-14)	-0.70%
sha256_var_witness_const_regression	1,369 (-10)	-0.73%