fix(nr_large): use spawn_blocking also around bash script execution

[pierugo-dfinity]

Similarly to #8547, this PR spawns the execution of the bash script itself as a blocking task since it also uses blocking I/O.

Unfortunately, I could not simply write

tokio::task::spawn_blocking(move || self.block_on_bash_script_from_session(&session, &script))
    .await
    .expect("Executing bash script task panicked")

because I also had to clone self, which is not Clone. Removing the self parameter from block_on_bash_script_from_session (which is not used) would not be practical either as we would have to adapt every call site.