get-balance and get-all-events migrated to v5

[nischitpra]

PR-Codex overview

This PR focuses on migrating the wallet and contract event functionalities from version 4 to version 5 of the thirdweb SDK, ensuring backward compatibility and implementing new methods for fetching wallet balances and contract events.

Detailed summary

• Replaced getSdk with thirdwebClient and updated balance fetching in get-balance.ts.
• Added new types ContractEventV4 and ContractEventV5 in event.ts for event handling.
• Introduced toContractEventV4Schema function for backward compatibility.
• Updated get-all-events.ts to use getContractEvents and map to ContractEventV4.
• Added unit tests for migration validation in migrationV5.test.ts.

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