test: add e2e to swap with snap account

[plasmacorral]

Description

Related issues

Fixes: 469

Manual testing steps

1. yarn build:test:mv2 then ENABLE_MV3=false yarn test:e2e:single test/e2e/accounts/snap-account-eth-swap.spec.ts --browser=firefox
2. yarn build:test then yarn test:e2e:single test/e2e/accounts/snap-account-eth-swap.spec.ts --browser=chrome

Screenshots/Recordings

Before

After

Pre-merge author checklist

• [x] I've followed MetaMask Contributor Docs and MetaMask Extension Coding Standards.
• [x] I've completed the PR template to the best of my ability
• [ ] I’ve included tests if applicable
• [ ] I’ve documented my code using JSDoc format if applicable
• [x] I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

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.