PartDesign: Sketch attached to the external body XY plane clones the body and attaches it to the pad

### Workbench affected?

Part Design

### Problem description

I have a body (named Body) and a Pad in it. I wanted to model another Body with a Padded sketch in it so I created a new body (named Body001) and a sketch and a Pad in it. But a strange thing happened when I attached the sketch, by accident, on the xy plane of the first body (the Body); the new pad included new sketch and somehow fused the first body (or rather a clone of it) with no record in the tree.

Here is video to demonstrate:

https://github.com/user-attachments/assets/5fb4b027-2f53-40cd-a7ba-a9a70a06d00e

### Steps to reproduce

(1) create a body (named Body)
(2) create a sketch ( a simple rectangle)
(3) pad the sketch (to get a box)

(4) create another body (Body001)
(5) create a sketch and by invoking Sketch command and clicking on the box in the first body to get "Body" in the Reference 1. Click ok and the sketch would open in X-Y plane of the first body.
(5) sketch a circle partially overlapping the box.
(6) Pad out the circle sketch and click ok. This will produce extrusion of the circle but without seam line, so it will look as it's fused to the box, and the first body (Body) would show it's hidden in the tree.

(7) un-hide the first Body and move it with transform tool.
There will be the the Body (box) on the screen + the Body001 which will look a fused object made up from the box and the circle. A sort of clone of the Body with added circle.

### Expected behavior

When creating a sketch and clicking on a face of an external body, there will be warning that the element is not suitable for attachment of the sketch. However double or triple (or double double) clicking on the external body selects it in the Reference 1 of the sketch attachment property, mapped to object's x-y plane.

This causes the strange cloning of the external body. It should not be allowed or if the intention is to allow attachment to an external body x-y or other plane it should not create further links, fusions etc.

### Actual behavior

Described above in the video.

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

```shell
OS: macOS 12.7.6
Architecture: x86_64
Version: 1.2.0dev.20251118 (Git shallow)
Build date: 2025/11/18 21:54:51
Build type: Release
Branch: main
Hash: be7d41dea75f7f2966d7b431d24f7060c6907339
Python 3.11.14, Qt 6.8.3, Coin 4.0.3, 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: English/United States (en_US)
Navigation Style/Orbit Style/Rotation Mode: Touchpad/Trackball Classic/Drag at cursor
Stylesheet/Theme/QtStyle: FreeCAD.qss/FreeCAD Dark/
Logical DPI/Physical DPI/Pixel Ratio: 72/128/1
Installed mods:
* MeshRemodel 1.10.37
* FreeCAD-themes 2025.6.4
* freecad.gears 1.3.0
* boltsfc 2022.11.5
* fasteners 0.5.43
* sheetmetal 0.7.58
```

### Last known good version (optional)

```shell

```