Function execute_explain 

async fn execute_explain(
    client: &Client,
    explain_db: &str,
    explain_schema: &str,
    actions: &[StagingAction],
    target: &ExplainTarget,
    target_typed_obj: &DatabaseObject,
    target_cluster: &str,
) -> Result<String, CliError>

Execute the staging actions, create the target, and run EXPLAIN.