fix(user attributes): LP-3626 - fix for setting a user attribute to null does not clear it in the User Profile.

Author: Enuviel

AndroidSDK/src/com/leanplum/internal/LeanplumInternal.java

@@ -532,10 +532,6 @@ public static <T> Map<String, T> validateAttributes(Map<String, T> attributes, S
       for (Map.Entry<String, T> entry : attributes.entrySet()) {
         T value = entry.getValue();
 
-        if (value == null) {
-          continue;
-        }
-
         // Validate lists.
         if (allowLists && value instanceof Iterable<?>) {
           boolean valid = true;
@@ -556,7 +552,7 @@ public static <T> Map<String, T> validateAttributes(Map<String, T> attributes, S
             Date date = CollectionUtil.uncheckedCast(value);
             value = CollectionUtil.uncheckedCast(date.getTime());
           }
-          if (!isValidScalarValue(value, argName)) {
+          if (value != null && !isValidScalarValue(value, argName)) {
             continue;
           }
         }