refactor(rd_gen_to_dag): removed assert

[kobayu858]

Description

Removed duplicate error checks. Added new error checks.

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How was this PR tested?

Notes for reviewers

[atsushi421]

@kobayu858
Could you explain where the duplicate part is?

[kobayu858]

@atsushi421

My explanation was insufficient. I apologize.
The existing assertions had incorrect conditions to begin with.

For example, the following section should be
in_links_num > 0 instead of in_links_num == 0.
Considering this premise, when in_links_num is 0, it can be detected by the match statement error LinkNumError::Input.

This occurred in three places, so I fixed it.

    assert!(
        in_links_num == 0,
        "LinkNumError::NoInput: dag_id={dag_id}, node_id={node_id}"
    );

    match in_links_num {
        1 => register_sink!(dag, node_data, sched_type, u64),
        2 => register_sink!(dag, node_data, sched_type, u64, u64),
        3 => register_sink!(dag, node_data, sched_type, u64, u64, u64),
        _ => Err(LinkNumError::Input(dag_id, node_id)),
    }

            LinkNumError::Input(dag_id, node_id) => {
                write!(f, "DAG#{dag_id} Node#{node_id} has no input links")
            }

[atsushi421]

I got it. LGTM.