Assembly: Doubleclicking an 'Exploded View' treenode, while Task already active, applies explosion to the normal drawing

### Problem description

When creating an 'exploded view' of an assembly,
and accidentilly activating that 'exploded view' from the treenode again (while the Task panel is already open), the 'explosion' settings are applied to the main model.
Undo/Redo records something, but can't reliable be used to undo the issue.

### Workbench affected?

Assembly

### Steps to reproduce

Steps to reproduce
1. Create a document
2. Create an assembly, and add 2 boxes to the assembly. put them side-by-side.
3. Create an exploded view.
4. Move one box so the movement gets recorded.
5. Now, without closing the Task pane, doubleclick that new 'Exploded_View' treenode
6. That box which you moved, now gets the translation applied to your drawing each time you doubleclick.
7. Pressing 'cancel' on the Task only reverts 1 movement, but the effects of the doubleclicks stay.

### Expected behavior

Doubleclicking an exploded view treenode,
when the 'Exploded View'-Task pane is already open,
shouldn't do anything

### Actual behavior

Doubleclicking an 'exploded view' treenode,
when the 'Exploded View'-Task pane is already open,
applies the explosion settings to your actual drawing.

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

```shell
OS: Ubuntu 24.04.4 LTS (KDE/plasmawayland/wayland)
Architecture: x86_64
Version: 26.3.0dev.20260902 (Git shallow) AppImage
Build date: 2026/09/02 02:30:22
Build type: Release
Branch: (HEAD detached at c68c45227)
Hash: c68c452275ec188f35c02f6b30aba880b3783cf1
Python 3.11.14, Qt 6.8.3, Coin 4.0.10 (bundled), Pivy 0.6.11 (bundled), Vtk 9.3.1, boost 1_86, Eigen3 3.4.0, PySide 6.8.3
shiboken 6.8.3, xerces-c 3.3.0, Clipper2 , IfcOpenShell 0.8.0, OCC 7.8.1
Locale: Dutch/Netherlands (nl_NL)
Stylesheet/Theme/QtStyle: FreeCAD.qss/FreeCAD Dark/
QPA/File dialog/Color dialog: xcb/via Qt/via Qt
Navigation Style/Orbit Style/Rotation Mode: CAD/Rounded Arcball/Window center
Logical DPI/Physical DPI/Pixel Ratio: 96/95.1083/1
OpenGL version/vendor/renderer: 4.6 (Compatibility Profile) Mesa 25.2.8-0ubuntu0.24.04.2/Intel/Mesa Intel(R) UHD Graphics (CML GT2)
```

### Last known good version (optional)

```shell
FreeCad 1.1.3 has the same isue, but is triggered slightly different.

Reproduce it by
0. Create an assembly containing 2 boxes.
1. Create Exploded View.
2. Move one box.
3. Close the Task pane
(otherwise doubleclicking the 'exploded view' treenode shows another bug)
4. doubleclick 'Exploded_View' treenode (this opens the Task panel again)
5. doubleclick 'Exploded_Views' treenode (the rename editor shows)
6. doubleclick 'Exploded_View' (This shows the bug in 1.1.3)

OS: Ubuntu 24.04.4 LTS (KDE/plasmawayland/wayland)
Architecture: x86_64
Version: 1.1.3.20260725 (Git shallow) AppImage
Build date: 2026/07/25 04:52:02
Build type: Release
Branch: grafted,grafted
Hash: 145529fe741292ff0b3977a01195bf0247425794
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 0.8.4, OCC 7.8.1
Locale: Dutch/Netherlands (nl_NL)
Navigation Style/Orbit Style/Rotation Mode: TinkerCAD/Rounded Arcball/Drag at cursor
Stylesheet/Theme/QtStyle: FreeCAD.qss/FreeCAD Light/
Logical DPI/Physical DPI/Pixel Ratio: 96/95.1083/1
Installed mods:
* Fasteners Workbench 0.5.65
* Parts Library 2026.7.30
* Woodworking 3.3.20260801
```

Start with the Assembly workbench's Exploded View treenode activation and the already-open Exploded View Task panel, reproducing the doubleclick sequence described in the issue. Trace how the active task handles repeated treenode activation and verify undo/redo behavior. Done means doubleclicking the treenode while the Task panel is open has no effect on the main assembly or its movement history.

Written by the indexing model from the issue text.