TechDraw: arc length dimension doesn't follow the standards

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Problem description

It would be good to improve the arc length dimension so that it follows the standards. Currently, it looks like this:


while it should look like this:


### Full version info

```shell
OS: Windows 10 build 19045
Word size of FreeCAD: 64-bit
Version: 0.22.0dev.36874 (Git)
Build type: Release
Branch: main
Hash: a4dd600ec6d5a53a9960cd9f8693d7d307b9e359
Python 3.11.8, Qt 5.15.13, Coin 4.0.2, Vtk 9.2.6, OCC 7.7.2
Locale: Polish/Poland (pl_PL)
```

### Subproject(s) affected?

Techdraw

### Anything else?

_No response_

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct