Add tests for updateScarbProject async/await behavior

[coderabbitai]

Description

Add comprehensive tests for the updateScarbProject function in both Cairo and Cairo Alpha packages to verify proper async/await behavior and prevent race conditions.

Background

The updateScarbProject function was recently fixed in #640 to properly await asynchronous operations (writeLibCairo and updateScarbToml). Previously, these functions were called without await, causing race conditions.

Requirements

The tests should:

1. Verify that writeLibCairo is properly awaited before updateScarbToml runs
2. Ensure sequential execution prevents race conditions
3. Test error handling when writeLibCairo fails
4. Verify that updateScarbToml doesn't run if writeLibCairo fails
5. For cairo_alpha: ensure the git/tag format for OpenZeppelin dependency is maintained

Files to add:

• packages/core/cairo/src/scripts/update-scarb-project.test.ts
• packages/core/cairo_alpha/src/scripts/update-scarb-project.test.ts

Related

• Original issue: Cairo: Support v3.0.0-alpha.1 #638 (review comment)
• Fix PR: Cairo: Use await async in update-scarb-project #640

Acceptance Criteria

• Tests verify writeLibCairo is awaited
• Tests verify sequential execution order
• Tests handle error scenarios appropriately
• Tests follow project's Ava testing conventions
• All tests pass and provide good coverage of the async behavior