(BE) update RollStats: set numDice in constructor

src/ts/rollstats.ts

@@ -26,8 +26,11 @@ export class RollStats {
 	maxDice = 10;
 	numDice = 4;
 
-	constructor() {
+	constructor(numDice?:number) {
 		this.resetCounts();
+		if (numDice) {
+			this.numDice = numDice;
+		}
 	}
 
 	resetCounts(): void {