feat(3075511177): support multitransaction

[danielgluskin-starkware]

Description of the Changes

Create a new method to receive MultiTransactionRequest. Define "transaction" type - a type and body for type safety.

Solves #3075511177

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Checklist

• [ ] New unit / functional tests have been added (whenever applicable).
• [ ] Docs have been updated (whenever relevant).
• [ ] PR title is follow the Conventional Commits convention: <type>[optional scope]: <description>, e.g: fix: prevent racing of requests