Fix selecting a template that doesn't exist

Fixes codesandbox#3454

Author: CompuIves

packages/app/src/app/components/CreateNewSandbox/CreateSandbox/TemplateList/TemplateList.tsx

@@ -287,6 +287,10 @@ export const TemplateList = ({
 
         const template = getTemplateByIndex(num - 1);
 
+        if (!template) {
+          return;
+        }
+
         track('Template Modal - Open Sandbox', { source: 'num-keys' });
         openSandbox(template.sandbox);
       }
@@ -309,6 +313,11 @@ export const TemplateList = ({
         e.preventDefault();
         const currentTemplate = getTemplateByIndex(focusedTemplateIndex);
 
+        if (!currentTemplate) {
+          // There are no sandboxes
+          return;
+        }
+
         track('Template Modal - Open Sandbox', { source: 'enter' });
         openSandbox(currentTemplate.sandbox, isMac ? e.metaKey : e.ctrlKey);
       }