Check return status of pacman for clean

[coolreader18]

I wasn't sure if this behavior was to some degree intentional, but it's tripped me up a couple times. Now, when you run paru -Sc and then ^C, it fully exits immediately, rather than just the pacman process being cancelled and having to ^C again the paru process. If it was intentional to not immediately exit on pacman error, maybe clean could just check whether it exited from a signal or not.