Increase user_id length limit from 30 to 35

[uxxman]

Describe the bug
The allowed user_id/customer_id character length is 35 while this lib restrict it to 30. So, user who has a user_id of length 31, 32 or 34 gets an error cannot be rendered: max_length=30 exceeded even though the same credentials work at the bank portal. Many users use their email address as alias and can easily reach the 30 letter limit.

English Translation:
Rules for the alias:
The alias must consist of at least 7 characters and can be a maximum of 35 characters long. All letters
letters, numbers and the special characters -_@ are permitted. Please note that a purely numerical alias is not possible. No distinction is made between upper and lower case
is not differentiated.