Interrapt G26

The user is able to create a new Mentor while using a surname that contains symbols that not match the given criteria (the only symbols that are accepted are "-" and ".", while the name field accepts symbols as "_")
Steps to reproduce:
1. Go to Mentors
2. Create a new Mentor with "_" symbol in surname
3. Observe the behavior
Expected result: A new Mentor should not be created. The Surname field should not accept symbols that are different from "-" and "."
Actual result: A new Mentor is created while using a different symbol than "-" and "." in Surname field