Headers on task panel not styled properly

[hasecilu]

This is from PartDesign Shaft Wizard command.
The problem occurs in both Qt5 and Qt6 compiled versions.

Related: #98

OS: Arch Linux (Hyprland/hyprland)
Word size of FreeCAD: 64-bit
Version: 1.1.0dev.38923 (Git) AppImage
Build type: Release
Branch: main
Hash: d20cb9e6ee198beb2bfd7e72d3dec0a575e3f28c
Python 3.11.9, Qt 5.15.13, Coin 4.0.3, Vtk 9.2.6, OCC 7.7.2
Locale: Spanish/Mexico (es_MX)
Stylesheet/Theme/QtStyle: OpenDark.qss/OpenDark/Qt default
Installed mods: 
  * FreeCAD-Movie 2024.2.15
  * freecad.gears 1.3.0
  * PieMenu 1.8.0
  * freecad_metal_workbench 0.0.1
  * Ship 2022.4.11
  * OpenTheme 2024.9.1
  * FreeGrid 2.0.0
  * Defeaturing 1.2.2
  * FreeCAD_SheetMetal 0.4.26
  * FreeCAD-Pyramids-and-Polyhedrons
  * GDML 2.0.0
  * Assembly4 0.50.10
  * FastenersWB 0.5.29
  * lattice2 1.0.0
  * Rocket 3.3.0
  * dodo 1.0.1
  * DidYouKnowThat
  * FreeCAD-motion
  * cadquery_module
  * Profiles 0.0.1
  * Alternate_OpenSCAD 1.0.0
  * osh-autodoc-workbench 0.2.3
  * CfdOF 1.27.10
  * freecad.plot 2022.4.17
  * SteelColumn (Disabled)
  * A2plus 0.4.67
  * kicadStepUpMod 11.2.4
  * frame 0.1.1
  * Curves 0.6.49
  * FreeCAD_assembly3 0.12.2
  * Render 2024.9.25