dev: test util in indexer to generate Starknet calldata

[tcoratger]

Description

In our Typescript indexer, we should introduce a utility function that generates random StarkNet calldata, providing a comprehensible implementation for each element of the array.

Currently, all the tests passes, but it's difficult to understand how the calldata is constructed and whether it is correct or not. The goal is to make this process more transparent and accessible.

Expected Feature

We need a function that:

• Accepts key parameters (e.g., to, etc.).
• Returns clean, well-documented calldata.
• Makes it easy for developers, including first-time contributors, to generate test calldata confidently.

By having a clear and reusable utility function, we can ensure that the test cases are easier to understand, and contributors can generate calldata reliably without needing deep knowledge of the internals.

Additional Context

This utility function will help improve the clarity of the test suite, making it easier for developers to construct valid calldata and reducing the potential for errors.

We should replace the existing test calldatas by call to this function.

Related #1414 (comment)