feat(prompts): add showInstructions opt-out

[dreyfus92]

What does this PR do?

adds showInstructions opt-out to select, multiselect and group-multiselect prompts

Closes #571

Type of change

• Bug fix
• Feature
• Refactor (no behavior change)
• Documentation
• Performance improvement
• Tests
• Chore (dependencies, CI, tooling)

Checklist

• pnpm test passes (or targeted tests for my change)
• pnpm format has been run
• I have added/updated tests for my changes (if applicable)
• I have added a changeset

AI-generated code disclosure

• This PR includes AI-generated code

[changeset-bot]

🦋 Changeset detected

Latest commit: e6bb6ba

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@clack/prompts	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pkg-pr-new]

• @example/basic

• @example/changesets

  npm i https://pkg.pr.new/@clack/core@574
  

  npm i https://pkg.pr.new/@clack/prompts@574
  

commit: e6bb6ba

[dreyfus92]

thank you both! 💜