chore(install-tests): Update test-installers workflow to use "bash" COMPASS-9383

[kraenhansen]

Description

After the upgrade of Node (which include an update to NPM) we're seeing consistent failures of the install tests because NPM in the new version has a bug related to passing arguments (after the --) to the command declared in an NPM script.

This is an attempt to work around the issue by avoiding the use of PowerShell when running the install tests.

Checklist

• New tests and/or benchmarks are included
• Documentation is changed or added
• If this change updates the UI, screenshots/videos are added and a design review is requested
• I have signed the MongoDB Contributor License Agreement (https://www.mongodb.com/legal/contributor-agreement)

Motivation and Context

• Bugfix
• New feature
• Dependency update
• Misc

Open Questions

Dependents

Types of changes

• Backport Needed
• Patch (non-breaking change which fixes an issue)
• Minor (non-breaking change which adds functionality)
• Major (fix or feature that would cause existing functionality to change)

[kraenhansen]

Seems to fix the issue: https://github.com/mongodb-js/compass/actions/runs/15157928474 (the failures seems like a flake and I'm re-running 🤞)