macOS x86 build doesn't respect dark mode (arm version does)

[levito]

Describe the bug
The macOS x86 build of FreeCAD 1.0 final doesn't respect dark mode: There is a bright title bar and open/save dialogs, and some UI elements are hardly readable.

The macOS arm build does respect dark mode, and the x86 build of RC2 did as well.

To Reproduce
Steps to reproduce the behavior:

1. On an Apple silicon Mac, download both the arm and x86 builds of FreeCAD 1.0
2. Switch to dark mode in macOS preferences
3. Open the arm build: the title bar will be dark, as it should
4. Open the x86 build: the title bar will be bright, but it should be dark as well

Screenshots
See the arm build on the left, the x86 build on the right, using default Dark theme:

See the arm build on the left, the x86 build on the right, using the Classic theme: