fix: blank page caused by disallowed synthetics (#7305)

Co-authored-by: Matin shafiei <[email protected]>

src/javascript/app/common/active_symbols.js

@@ -26,7 +26,7 @@ const submarket_order = {
 };
 
 const ActiveSymbols = (() => {
-    const groupBy = (xs, key) => (
+    const groupBy = (xs = [], key) => (
         xs.reduce((rv, x) => {
             (rv[x[key]] = rv[x[key]] || []).push(x);
             return rv;