Several small improvements

Bring back the password preview button

The revealPasswordButtonShown property has been deprecated and PlasmaExtras/PasswordField is recommended. But in the long term, we want to reduce the dependence of the greeter on Plasma, so we don't follow the advice, but a homemade button was made.

Hide menuBar items gradually

You can set an "expand order" for a menuBar item, and then item with a lower order will be collapsed earlier if there is not enough space.

Here the power buttons have order 1, the network widget button has order 2 and the session button has order 3:

Show Caps Lock or Num Lock enabled

Provide some time to read messages from PAM

Sometimes the PAM module sends some messages immediately before successful authentication, and the user barely has time to see them. Added a simple mechanism that allows to slightly delay the start of the session so that the user can read all messages.

Looked in GDM, the time it takes to view a message is calculated as 48 milliseconds per character. Implemented similar here.

Also, added that if an identical message is already in the list, extra time is not allocated. This has proven useful for fingerprint authentication, for example; it spams you with repeated messages if it fails to read your fingerprint. Which results in an excessively long timeout after authentication.