chore: failed build commands should fail the build

Description

For some reason, we are swallowing build errors instead of failing the build.

This MR makes execa throw an error if the build task fails

I noticed it because we now have a type error on the main branch:

src/common/language_server/language_client_wrapper.ts(223,11): error TS2353: Object literal may only specify known properties, and 'toolApproval' does not exist in type '{ executor?: DuoWorkflowExecutorType | undefined; useDocker?: boolean | undefined; dockerSocket?: string | undefined; graph?: string | undefined; }'.
Command failed with exit code 2: tsc -p /builds/gitlab-org/gitlab-vscode-extension

How has this been tested?

The pipeline now fails.

I'll release the LS and update it in VS Code Extension, then the pipeline succeeds and we can merge this.

Screenshots (if appropriate)

What CHANGELOG entry will this MR create?

• fix: Bug fix fixes - a user-facing issue in production - included in changelog
• feature: New feature - a user-facing change which adds functionality - included in changelog
• BREAKING CHANGE: (fix or feature that would cause existing functionality to change) - should bump major version, mentioned in the changelog
• None - other non-user-facing changes