"""Remove the `if __name__ == "__main__":` block from the source code.

This function parses the provided Python source code and identifies the block guarded by the
`if __name__ == "__main__":` condition. It then removes this block and returns the modified
source code. If no such block is found, the original source code is returned unchanged.

Args:
    source_code (str): The Python source code as a string.

Returns:
    str: The source code with the `if __name__ == "__main__":` block removed, or the original
        source code if no such block is found.
"""
You should write code starting with:
import ast

def remove_main_block(source_code: str) -> str:
    # TODO: Implement this function
    pass

