"Ask to shutdown" preference does not take effect

### What Happened?

On a fresh install of 8.1 + updates, I changed the preference of the power button to "Ask to shutdown". It worked the first time, but later on, pressing the power button does nothing, or sometimes it suspends.

### Steps to Reproduce

1. In power settings, change the power button behaviour to "Ask to shutdown".
2. Press the power button to shutdown across a few sessions.

### Expected Behavior

It should present the shutdown dialog. Instead, it either does nothing or suspends the machine.

### OS Version

8.x (Circe)

### OS Architecture

amd64 (on most hardwares)

### Session Type

Secure Session (Wayland, This is the default)

### Software Version

Latest release (I have run all updates)

### Log Output

```shell

```

### Hardware Info

It's a Lenovo Thinkbook. Here's the about dialog.

Start by reproducing the power-button behavior from the reported steps on the default Wayland session, then inspect the power-button preference handling in the settings-power Switchboard plug. Done means that selecting "Ask to shutdown" consistently presents the shutdown dialog across multiple sessions instead of doing nothing or suspending.

Written by the indexing model from the issue text.