fix(nargo): Switch order of writing acir file and acir checksum file

[vezenovm]

Related issue(s)

Quick fix found while working on a separate project so no issue

Description

During nargo compile the checksum file is being written first followed by the acir file. We set an extension .acir.sha256 for the sha checksum. When we reset the extension we were mistakenly only resetting the last extension of .sha256 so the acir file being written to target was .acir.acir.

Summary of changes

We write the ACIR file followed by the checksum now. Running nargo compile p for example will now correctly give p.acir and p.acir.sha256.

Dependency additions / changes

Test additions / changes

Checklist

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt with default settings.
• I have linked this PR to the issue(s) that it resolves.
• I have reviewed the changes on GitHub, line by line.
• I have ensured all changes are covered in the description.
• This PR requires documentation updates when merged.

Additional context

[Savio-Sou]

Confirming that this doesn't require doc updates right?

[TomAFrench]

Yes, this shouldn't require any doc updates (I don't think we document the checksum currently anyway)