[Bug] Slider widget not displaying

**Describe the bug**
When using the slider widget only the label is showed. This might be due to bad configuration though.

**To Reproduce**
Just add the slider widget in the config file as so :
"slider": {
"label": "󰍬",
"cmd_setter": "wpctl set-volume @DEFAULT_AUDIO_SOURCE@ $value",
"cmd_getter": "wpctl get-volume @DEFAULT_AUDIO_SOURCE@ | awk -F ' ' '{print $2*100}'"
},

**Expected behavior**
When the slider widget is enabled, a slider should be shown.

**Screenshots**

**Desktop (please complete the following information):**
- OS: Fedora Workstation 44 Beta
- Version 0.12.6

Start by reproducing the issue with the provided slider configuration on Fedora and the reported version, checking whether the widget renders beyond its label. Verify the `cmd_setter` and `cmd_getter` commands and confirm that enabling the slider produces a visible control rather than only the label.

Written by the indexing model from the issue text.