add adcMultiplierOverride validation

src/validation/config/power.ts

@@ -1,4 +1,4 @@
-import { IsBoolean, IsEnum, IsInt } from "class-validator";
+import { IsBoolean, IsEnum, IsInt, Max, Min } from "class-validator";
 
 import { Protobuf } from "@meshtastic/meshtasticjs";
 
@@ -13,6 +13,8 @@ export class PowerValidation implements Protobuf.Config_PowerConfig {
   onBatteryShutdownAfterSecs: number;
 
   @IsInt()
+  @Min(2)
+  @Max(4)
   adcMultiplierOverride: number;
 
   @IsInt()