fix: update OPTIMISM_TESTNET to OPTIMISM_SEPOLIA

[sahar-fehri]

Explanation

This PR replaces the reference to OP goerli to OP sepolia. It also renames the variable OPTIMISM_TESTNET to OPTIMISM_SEPOLIA.

Only made this change on the transaction controller.

Renaming the variable and switching to Sepolia is a breaking change, please use Sepolia and OPTIMISM_SEPOLIA instead of OPTIMISM_TESTNET.

References

• Fixes https://github.com/MetaMask/mobile-planning/issues/1569
• Related to #67890

Changelog

@metamask/transaction-controller

Removed

• BREAKING: Renamed OPTIMISM_TESTNET to OPTIMISM_SEPOLIA and updated the chainId accordingly.
• BREAKING: Updated the etherscan subdomain that was for OPTIMISM_TESTNET from goerli to sepolia.

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've highlighted breaking changes using the "BREAKING" category above as appropriate

[mcmire]

Looks good.