chore(modals): upgrade container-modal

[hzhu]

Description

Upgrades @zendeskgarden/container-modal to latest version. This addresses a bug where choosing a Select option within a modal dismisses the modal.

Detail

Verified locally that choosing a Select option within a modal no longer dismisses the modal.

Checklist

• 👌 design updates are Garden Designer approved (add the
  designer as a reviewer)
• 🌐 demo is up-to-date (yarn start)
• ⬅️ renders as expected with reversed (RTL) direction
• 🤘 renders as expected with Bedrock CSS (?bedrock)
• ♿ analyzed via axe and evaluated using VoiceOver
• 💂‍♂️ includes new unit tests
• 📝 tested in Chrome, Firefox, Safari, Edge, and IE11

[coveralls]

Coverage remained the same at 95.149% when pulling 6fe878e on hzhu/modals-container-upgrade into 52e80f7 on main.