refactor getGateDisplayCount

Author: shtukas

dotcom-rendering/src/components/SignInGateSelector.importable.tsx

@@ -375,9 +375,11 @@ const decideShowDefaultGate = (): ShowGateValues => {
 };
 
 const getGateDisplayCount = (): number => {
-	const rawValue = storage.local.getRaw('gate_display_count');
-	const count = parseInt(rawValue ?? '0', 10);
-	return count;
+    const count = parseInt(storage.local.getRaw('gate_display_count'), 10);
+    if (Number.isInteger(count)) {
+        return count;
+    }
+    return 0;
 };
 
 const incrementGateDisplayCount = () => {