test: Unit test for wallet/rpc.rs

[bit-aloo]

Issue Description:
This issue highlights the need for unit tests in our wallet/rpc.rs file. Currently, several methods and functions in this file are untested, which could lead to potential issues in the future.

Objective:
Write unit tests for each method and associated function in the wallet/rpc.rs file.

Details:

• Cover all methods and functions with appropriate test cases.
• Ensure tests validate functionality, handle edge cases, and check error conditions.
• Integrate the tests into our existing test suite.

[Raj]

Theres nothing much to test for rpc, and most stuffs are covered in IT.