v208.go is seriously broken as it misses an ID() check. We need to no-op and remigrate all of the u2f keys.
See #18756
Signed-off-by: Andrew Thornton <art27@cantab.net>
Unfortunately credentialIDs in u2f are 255 bytes long which with base32 encoding
becomes 408 bytes. The default size of a xorm string field is only a VARCHAR(255)
This problem is not apparent on SQLite because strings get mapped to TEXT there.
Fix#18727
Signed-off-by: Andrew Thornton <art27@cantab.net>