Fix the new user validator for name and age

A pytest for your signup check wrapped the call in try with except Exception: pass, so it passed whether the check raised or not. The team now has the check return a reason code, so a test can assert which rule rejected the user.

An assistant wrote validate_new_user(name, age). It is in the editor. It has a bug. Find it and fix it.

Input and output:

• name: the name as typed. The only whitespace characters it can contain are spaces, tabs, newlines and carriage returns.
• age: the age, an integer. It can be negative or very large.
• Return one of "name_required", "age_negative", "age_too_large" or "ok".

Rules the tests check:

• Check these rules in this order, and return the code of the first one that applies:
  1. The name is blank: empty, or only whitespace. Return "name_required".
  2. The age is below 0. Return "age_negative".
  3. The age is above 130. Return "age_too_large".
• If none applies, return "ok". Ages 0 and 130 are both valid.
• A name with whitespace around real characters, such as " bob ", is a valid name.