fix: snaps unable to call wallet_switchEthereumChain when they have no accounts permitted

[jiexi]

Description

A helper function used for facilitating chain switching and permissions related to it incorrectly requires accounts to permitted before setting the per dapp selected network for that dapp. This seems to be a scenario that is possible in Snaps specifically making it so that Snaps are unable to switch their selected network.

The fix is to remove this requirement for accounts as it isn't truly needed in the first place.

Related issues

Fixes:

Manual testing steps

1. Visit https://metamask.github.io/snaps/test-snaps/latest/
2. Connect to Ethereum Provider Snap
3. Change the Select Chain Dropdown
4. Click Get Chain Id
5. Should match each time

Screenshots/Recordings

Before

After

https://github.com/user-attachments/assets/48d65c48-c61c-44dd-8dbd-aa97f4ef9958

Pre-merge author checklist

• [ ] I’ve followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards.
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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).
• [ ] I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.