DC Relay Module for Switching ~200 VDC @ 1.4A with Arduino Controller
Switching off the AC input won't switch off the output until the power supply capacitors have discharged. This may take 0.2 to 2 s or so depending on the load so it is unlikely to provide you with a solution to your problem.



simulate this circuit &ndash; Schematic created using CircuitLab
Figure 1. Equivalent circuit.
Arcing is particularly destructive with un-snubbed inductive loads as they generate a high voltage across the opening contacts in an effort to keep the current going through the inductor. In this case you don't have any inductance and you're not changing the current - you are only diverting it from the LED to the switch.
Your switch, whether mechanical or electrical, only has to be rated for the LED current (DC) and the maximum voltage to be switched.