Implement `AccountSelector` component

[FrederikBolding]

We should introduce a component that lets a Snap select from the accounts that the user has without exposing all of the accounts to the Snap.

State
The selected account should be reflected in state with an object containing:

• addresses: CAIP10Address[]
• accountId: string (only if the Snap owns the account)

Props

• hideExternalAccounts?: boolean (should hide non-owned accounts)
• chainIds?: CAIP2ChainId[]
• switchSelectedAccount?: boolean (should switch the globally selected network)
• selectedAddress?: CAIP10Address

[eriknson]

LoFi spec: https://www.figma.com/board/1M8AhtE2DHMnahTugMBqie/Core-Accounts-Components?node-id=1-403&t=OkCit1tDxKvbO0QD-1

[eriknson]

Design: https://www.figma.com/design/gHWl7G8ih3YXesly2XaA0R/Snaps-DS?node-id=627-4667&t=k2DDgjWRUqW2yedP-1