feat: Select all for synchronous select

[cccs-RyanK]

SUMMARY

This PR adds a 'select all' functionality to the synchronous Select component. This functionality has been requested by a large number of users and contributors. The select component has been previously split into sync and async components to simplify the code. The sync select component is the more widely used component, and a select all for the sync case is much easier to implement. This PR simply adds the option for selectAllEnabled only when the select component is in multi-select mode. The option is by default set to false. This is part of the greater task to rework the select component for the select all functionality outlined by @michael-s-molina in this PR: #20143

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

In storybook, go to the select component -> interactive select and set the mode to multi and selectAllEnabled to True

ADDITIONAL INFORMATION

• Has associated issue: "Select All" functionality needed in column select #18247 (comment)
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API