refactor: combine AccountsController listMultichainAccounts and listAccounts usage where appropriate

[ffmcgee725]

Description

In app/core/Permissions/index.ts, we have some utility functions which are looking to reduce repeated code on, such as getPermittedCaipAccountIdsByHostname and getPermittedEvmAddressesByHostname, which share very similar structure:

• Both take the same parameters (state and hostname)
• Both extract the subject from state
• Both use similar helper functions (getCaipAccountIdsFromSubject and getEvmAddessesFromSubject)
• Both return empty arrays if no subject is found

The helper functions getCaipAccountIdsFromSubject and getEvmAddessesFromSubject also share similar structure:

• Both extract caveats from the subject's permissions
• Both find a specific caveat by type
• Both return empty arrays if no caveats are found

The refactoring I propose introduces two generic helper functions:

• getDataFromSubject<T>: A generic function that handles the common pattern of extracting data from a subject's permissions and caveats. It takes a type parameter T and an extractor function that knows how to get the specific type of data from a caveat.
• getPermittedDataByHostname<T>: A generic function that handles the common pattern of getting permitted data by hostname. It takes a type parameter T and an extractor function that knows how to get the specific type of data from a subject.

Related issues

Fixes: https://github.com/MetaMask/MetaMask-planning/issues/5115

Manual testing steps

There should be no user or dapp facing difference in behavior.

Screenshots/Recordings

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After

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Pre-merge reviewer checklist

• [ ] I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
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