Greeter: Password check doesn't work when changing first entry

In Tails 3.0.1 (and previous), at Greeter, when setting an administration password the following way, you don’t get any error message, but can’t get and admin terminal neither:

Procedure
=

• go to the admin password part of the Greeter
• in the first field type your password, but wrongly (let’s say “possword”)
• in the second field type the right one (let’s say “password”)

You get a notice that it doesn’t match

• change the password in the first field to the right one (“password”)

You get a notice that it matches

• Start Tails

Result
==

Can’t open/use an admin password.

Feature Branch: https://salsa.debian.org/tails-team/tails/merge_requests/39/commits

Related issues

• Related to #12386 (closed)
• Related to #14544
• Blocks #16209
• Blocked by #16095 (closed)

Original created by @mercedes508 on 13447 (Redmine)