Create documentation for Sandbox Mocked Withdrawals

[JoelGama]

Create documentation for Sandbox Mocked Withdrawals

CRY-5199

[Copilot]

Pull Request Overview

This PR adds comprehensive documentation for Sandbox Mocked Withdrawals, explaining the purpose, supported networks, configuration, and code examples to simulate withdrawal flows.

• Added an overview and rationale for using mocked withdrawals.
• Detailed configuration and example usage, including code snippets in JSON and TypeScript.

Comments suppressed due to low confidence (1)

_sandboxmockedwithdrawals.md:58

• [nitpick] The documentation uses different casing for mock type values compared to the table where 'MOCK_ENABLED' is used. Consider standardizing the naming convention (either all uppercase or all lowercase) for clarity and consistency.

default: "mock-enabled",

[waldyrious]

Thanks for considering my suggestions, @JoelGama. I cannot unresolve the threads above, but I left additional comments in a couple of them. Please take a look at your convenience.