[Hotfix] Update usage.md

[makylfang]

PR

Describe your changes

• Update usage.md with wallet_switchEtheremNetwork and wallet_addEthereumNetwork usage

Checklist before requesting a review

• You have performed a self-review of your own code
• You are using approved terminology
• Your changes have been tested locally
• Your code builds clean without any errors or warnings

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[shaloo]

@makylfang should I merge it? can ignore branch name check failure i guess?