chore: Remove network-controller dependency for chain-agnostic-permission

[FrederikBolding]

Explanation

Remove network-controller dependency for chain-agnostic-permission as it brings in a massive amount of dependencies and is only used for a single type union that contains string anyway.

The additional dependencies becomes hard to manage when using chain-agnostic-permission outside a MetaMask client (e.g. in Snaps).

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Note

Removes the @metamask/network-controller dependency and eliminates its type usage.

• Drops @metamask/network-controller from package.json and yarn.lock
• Updates caip25Permission.ts to remove the import and change findNetworkClientIdByChainId return type from NetworkClientId to string
• Notes the change in CHANGELOG.md

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[jiexi]

should this be in a Removed section? Doesn't really matter though