Rapid volume changes leave icon in an uncertain state

### What Happened?

Changing volume too quickly would result in a weird icon in a mixed state. This could be achieved either via a simple slider flick or a quick mouse wheel scroll on top of icon in the panel (managed to do this with touchpad and free scrolling wheel)

https://github.com/user-attachments/assets/1fd94abf-70d9-4b89-8af3-415bc2c7b12a

### Steps to Reproduce

1. Change volume quickly
2. Observe the result

### Expected Behavior

Fluid state change of new icon (really love them)

### OS Version

Other Linux (fedora 44, gtk 4.22.4)

### OS Architecture

amd64 (on most hardwares)

### Session Type

Secure Session (Wayland, This is the default)

### Software Version

Early Access or Compiled from git
wingpanel https://github.com/elementary/wingpanel/commit/046d7945d066e37c1ec24687a32cae3c11114b75
panel-sound 80406f132128cbe6efdba219174f60fb5e7e466c

### Log Output

```shell

```

### Hardware Info

_No response_

Start by reproducing rapid slider flicks and mouse-wheel scrolling in panel-sound on the reported Wayland setup, then follow how volume updates drive the icon state. Done means the icon changes fluidly and never remains in a mixed or uncertain state during fast volume changes.

Written by the indexing model from the issue text.