Fix accidental new lines

Author: tejasd

firebase-crashlytics/src/main/java/com/google/firebase/crashlytics/internal/metadata/UserMetadata.java

@@ -22,7 +22,6 @@
 import com.google.firebase.crashlytics.internal.concurrency.CrashlyticsWorkers;
 import com.google.firebase.crashlytics.internal.model.CrashlyticsReport;
 import com.google.firebase.crashlytics.internal.persistence.FileStore;
-
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
@@ -169,7 +168,6 @@ public Map<String, String> getCustomKeys(Map<String, String> eventKeys) {
   }
 
   /**
-   *
    * @return defensive copy of the custom keys.
    */
   public Map<String, String> getCustomKeys() {