Birthday corrupted when imported from phpBB3

[TK-3375]

After merging my phpBB3 forum with MyBB I started getting errors when editing user profiles regarding the birthday. I might be wrong but I believe there are non wanted spaces added when importing the data : like "18- 4-1972-"

Forum gets confused and in most cases simply left the dropdown menu empty for "month" in user profile page. Unless you select a month, you can't alter that user account.

A quick (and dirty ?) fix I did was removing spaces from that field in the database :

UPDATE mybb_users SET birthday = REPLACE(birthday, ' ', '');

Not sure how good a solution it is though. See pictures on my discord post here : https://discord.com/channels/215876847634743296/215877079911104522/1021354570233954355