chore: remove @metamask/ethjs package

[cryptodev-2s]

Description

This PR introduces the following changes:
• Removes the @metamask/ethjs package.
• Replaces the global variable global.eth with the existing global.ethereumProvider (an instance of StreamProvider from web3-stream-provider package).
• Updates all instances of getCode to use a manual sendAsync call for the eth_getCode method, as StreamProvider does not include getCode, unlike ethjs.
• Substitutes the use of ethjs contracts with Contract instances from the @ethersproject/contracts library.

Related issues

Fixes:

Manual testing steps

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Screenshots/Recordings

Before

After

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Extension Coding Standards.
• 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
• 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.

[github-actions]

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[cryptodev-2s]

@metamaskbot update-policies

[socket-security]

Removed dependencies detected. Learn more about Socket for GitHub ↗︎

🚮 Removed packages: npm/@metamask/[email protected], npm/@metamask/[email protected], npm/[email protected]

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[cryptodev-2s]

@metamaskbot update-policies

[metamaskbot]

Policies updated.
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