profile: prevent accidental "undefined" as profile identifier

Author: abarisain

src/BatchProfile.ts

@@ -48,6 +48,9 @@ export const BatchProfile = {
    * If a profile already exists, this device will be attached to it. Must not be longer than 1024 characters.
    */
   identify: (identifier: string | null): void => {
+    if (typeof identifier === "undefined") {
+      return;
+    }
     RNBatch.profile_identify(identifier);
   },