Query results fail to load when stats field is missing

Adds an extra check to prevent throwing a TypeError when the
stats response does not have one of the expected fields.
diff --git a/app/addons/documents/mango/components/ExecutionStats.js b/app/addons/documents/mango/components/ExecutionStats.js
index 5c043d1..48b815a 100644
--- a/app/addons/documents/mango/components/ExecutionStats.js
+++ b/app/addons/documents/mango/components/ExecutionStats.js
@@ -53,8 +53,11 @@
   }
 
   executionStatsLine(title, value, alwaysShow = false, units = "") {
-    const hasValue = value === 0 && !alwaysShow ? "false" : "true";
-    return <div data-status={hasValue}>{title + ": "}<span className="value">{value.toLocaleString()} {units}</span></div>;
+    if (typeof value === 'number') {
+      const hasValue = value === 0 && !alwaysShow ? "false" : "true";
+      return <div data-status={hasValue}>{title + ": "}<span className="value">{value.toLocaleString()} {units}</span></div>;
+    }
+    return null;
   }
 
   executionStatsPopupComponent(executionStats) {