Fix null reference on isError check

Summary: Fixed new error which appeared in logview after last release. See task T91245438 for details.

Reviewed By: passy

Differential Revision: D28569848

fbshipit-source-id: a4b622d4387aa41ecc4db269e05c5315669df250

desktop/app/src/utils/errors.tsx

@@ -26,7 +26,8 @@ declare global {
 export function isError(obj: any): obj is Error {
   return (
     obj instanceof Error ||
-    (obj.name &&
+    (obj &&
+      obj.name &&
       typeof obj.name === 'string' &&
       obj.message &&
       typeof obj.message === 'string' &&