We store an encrypted version of the passwords for vendor's interfaces, but we don't utf8 decode it after it is decrypted
Test plan:
0. Do not apply this patch
1. Create or edit a vendor and add at least one interface with non ascii
characters, eg. émyPassword❤
2. Go to the detail view of the vendor and click the "Show password"
link
=> The password is not correctly utf8-decoded
3. Apply this patch, repeat 2
=> The password is correctly displayed
4. Repeat 1 and 2
=> The password is correctly displayed
Note that maybe we should make sure the encrypt_hex is getting a valid
utf8-encoded variable.