Refactor usage in the function itself

Author: Mohammadreza Ghorbani

src/javascript/_common/base/currency_base.js

@@ -28,7 +28,7 @@ const formatMoney = (currency_value, amount, exclude_currency, decimals = 0, min
     return sign + (exclude_currency ? money : money + formatCurrency(currency_value));
 };
 
-const formatCurrency = currency => `<span class="symbols">&nbsp;${getCurrencyDisplayCode(currency)}</span>`; // defined in binary-style
+const formatCurrency = currency => currency ? `<span class="symbols">&nbsp;${getCurrencyDisplayCode(currency)}</span>` : ''; // defined in binary-style
 
 const addComma = (num, decimal_points, is_crypto) => {
     let number = String(num || 0).replace(/,/g, '');

src/javascript/app/pages/user/account/settings/self_exclusion.js

@@ -52,7 +52,7 @@ const SelfExclusion = (() => {
 
         currency = Client.get('currency');
 
-        $('.append_currency').after(currency ? Currency.formatCurrency(currency) : '');
+        $('.append_currency').after(Currency.formatCurrency(currency));
 
         // svg is only applicable for CR clients
         is_svg_client = Client.get('landing_company_shortcode') === 'svg';