lomiri greeter: in usageMode 'desktop' the login prompt is moved to far up if the OSK pops in

How to reproduce this issue:

• Install Debian 13 minimal on physical hardware (e.g. a notebook) or a VM, and run apt install lomiri afterwards. Reboot.
• This issue happens in Lomiri Greeter, so don't log into the Lomiri session.
• Click on the keyboard icon in the username / password prompt of the greeter
• Observe.
• As a 2nd step: Then switch to a TTY and add this content:

[com.lomiri.Shell]
usage-mode='Staged'

to a new file named /usr/share/glib2.0/schemas/99_lomiri.override

• Run glib-compile-schemas /usr/share/glib2.0/schemas to activate the new override.
• Restart LightDM (invoke-rc.d lightdm restart)

What you will observe:

• The OSK comes up and the username / password field is moved way up to a place near the top border of the screen (TOO FAR)
• After you have enforced the window manager mode to "Staged", the username/password field behaves well and is only moved a little bit up

What should happen:

In 'windowed' or Desktop mode, the OSK should move the username/password field up slightly, so that the user experience matches with the behaviour in staged mode