Update ember-power-select, PowerSelectMultiple -> @multiple

[RobbieTheWagner]

📌 Summary

This PR updates ember-power-select to the latest version and migrates from PowerSelectMultiple to using @multiple, which is the new API for multiple selects and PowerSelectMultiple is deprecated.

🛠️ Detailed description

📸 Screenshots

🔗 External links

Jira ticket: HDS-5725

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👀 Component checklist

• Percy was checked for any visual regression
• A changelog entry was added via Changesets if needed (see templates here)

💬 Please consider using conventional comments when reviewing this PR.

📋 PCI review checklist

• If applicable, I've documented a plan to revert these changes if they require more than reverting the pull request.
• If applicable, I've worked with GRC to document the impact of any changes to security controls.
  Examples of changes to controls include access controls, encryption, logging, etc.
• If applicable, I've worked with GRC to ensure compliance due to a significant change to the in-scope PCI environment.
  Examples include changes to operating systems, ports, protocols, services, cryptography-related components, PII processing code, etc.

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[aklkv]

this potentially breaking, I think to be safe we should target v5 for this change, maybe.

[RobbieTheWagner]

this potentially breaking, I think to be safe we should target v5 for this change, maybe.

What do you think is breaking?

[aklkv]

this potentially breaking, I think to be safe we should target v5 for this change, maybe.

What do you think is breaking?

Since there are consumer that BYO version of power select which might be lower then 8.11 where this API has been introduced we might run into issues. Maybe it's worth spinnning up RC build to test out on consumer but given that v5 is around the corner it might be just safer to target major release

[MelSumner]

1. It does not look like this changes how our consumers would invoke the component, so I'm not sure I agree that it's a breaking change.
2. Is there a Jira ticket for this issue?
3. A changelog entry is needed.

[KristinLBradley]

@RobbieTheWagner to follow up, what would you like the next steps to be for your PR? The HDS team discussed and this would be considered a breaking change for consumers using the older power-select-version and would require testing within consumer repositories to catch any potential issues before release. Would you like us to target the upgrade for next major HDS release sometime next year?

Quick searches I tried for related references:
(not all of these would matter or be affected by an upgrade, of course)

• "<PowerSelectMultiple" references: https://github.com/search?q=org%3Ahashicorp+%3CPowerSelectMultiple+-repo%3Ahashicorp%2Fdesign-system&type=code
• "power-select-multiple" references: org:hashicorp power-select-multiple -repo:hashicorp/design-system
• "ember-power-select" library references: https://github.com/search?q=org%3Ahashicorp+%22ember-power-select%22%3A+-repo%3Ahashicorp%2Fdesign-system&type=code