0% volume and mute have the same icon, but behave different.

## What Happened

Decreasing the volume all the way down with the mouse scroll and muting the sound (keyboard shortcut or switch) have different behaviours, but show the same icon:

- 0% Volume - No yellow icon feedback when audio is playing, no "pop" sound when activated, sound enabled switch enabled, mute icon.
- Mute - Yellow icon feedback when audio is playing, "pop sound" when activated, sound enabled switch disabled, mute icon

## Expected Behavior

Either:
- Decreasing the volume to 0% should show an empty bar and normal icon without "darkened waves".
- Decreasing the volume to 0% should behave like pressing the mute keyboard shortcut or disabling the sound enabled switch

## Steps to Reproduce

1. Decrease the volume to 0% using the mouse scroll on the volume icon
2. Play a sound: Check icon, sound is playing yellow feedback, sound enabled switch.
3. Stop the sound.
4. Increase the volume using the mouse scroll on the volume icon.
4. Mute the sound either by keyboard shortcut or disabling the sound enabled switch: Check icon, sound is playing yellow feedback, sound enabled switch.

## Platform Information

elementary OS 5.1.7 Hera