Assembly: there is no way for dragging with multiple joints involved after fixing #27014

### Problem description

Hi,
In current FreeCAD implementation only the closest joint to the dragged object is recomputed.

https://github.com/user-attachments/assets/e82ac834-bbe3-41c6-9564-8d18fa26cdfd

But there **was** an workaround, that allowed moving multiple joints and the same time: grounded joint + transform tool:

https://github.com/user-attachments/assets/19a518c5-b2f0-4668-838f-d638bf86cf1c

**Version: 1.1.1.20260414 (Git shallow) AppImage
Build date: 2026/04/14 22:09:59**

Since moving grounded object is not allowed anymore (since https://github.com/FreeCAD/FreeCAD/issues/27014), such workaround is not possible. Without the grounded joint, the assembly will not follow the object moved with the transform tool:

https://github.com/user-attachments/assets/d41f33b6-b908-4413-bc00-ad4930edcdec

**Version: 1.2.0dev.20260512 (Git shallow) AppImage
Build date: 2026/05/12 17:54:42**

As side note: recreating this dragging demo in VR https://youtu.be/6aVT2NHf4vE?si=h-TxmnAMiNr5AUVk&t=38 is not possible anymore too.

### Workbench affected?

Assembly

### Steps to reproduce

1. Open the attached file:
[6axis-robot-forced-new.zip](https://github.com/user-attachments/files/27776829/6axis-robot-forced-new.zip)
2. Move arm-axis5 with the transform tool
3. Delete GroundedJoint001 and move arm-axis5 again

### Expected behavior

The robot assembly follows the arm-axis5.

### Actual behavior

There is no way to force the assembly to follow the moved object.

### Development version About Info (in Safe Mode)

```shell
OS: Fedora Linux 43 (KDE Plasma Desktop Edition) (KDE/plasma/wayland)
Architecture: x86_64
Version: 1.2.0dev.20260512 (Git shallow) AppImage
Build date: 2026/05/12 17:54:42
Build type: Release
Branch: grafted,grafted
Hash: 758570d19c79cc4cf8b1e198b5568e7263e8e6d8
Python 3.11.14, Qt 6.8.3, Coin 4.0.8, Vtk 9.3.1, boost 1_86, Eigen3 3.4.0, PySide 6.8.3
shiboken 6.8.3, xerces-c 3.3.0, IfcOpenShell 0.8.2, OCC 7.8.1
Locale: Polish/Poland (pl_PL)
Stylesheet/Theme/QtStyle: FreeCAD.qss/FreeCAD Light/
Navigation Style/Orbit Style/Rotation Mode: CAD/Rounded Arcball/Window center
Logical DPI/Physical DPI/Pixel Ratio: 96/93.1131/1
```

### Last known good version (optional)

```shell

```