In Python 3.11, regex have undergone changes in
how they handle Unicode characters. In Python3.11,
global flags must be placed right at the start of a
regular expression. The following regex:
validators.RegexValidator(r'^(?u)[^/]+$')
must become:
validators.RegexValidator(r'(?u)^[^/]+$')
Closes-Bug: #2036378
Change-Id: I3884ae5b3a32e33077cf3efeac649ac0c615fdda