Long bond appears behind the structure after Copy-Paste in Flex Mode

[Zhirnoff]

Description:
In Flex Mode, when copying and pasting a structure that contains a long bond, the long bond is incorrectly rendered behind the structure, instead of appearing above the monomers as expected. This issue causes visual inconsistencies and makes it difficult to interpret the molecular connections correctly.

Steps to Reproduce

1. Switch to Flex Mode in Macromolecules.
2. Draw or load a structure that contains a long bond.

3. Copy (Ctrl+C) and Paste (Ctrl+V) the structure onto the canvas.
4. Observe the placement of the long bond in the newly pasted structure.

Actual behavior
The long bond appears behind the monomers, making it difficult to see and misrepresenting the intended structure.

Expected behavior
The long bond should always appear on top of the structure, maintaining its original placement and visibility.

Desktop:

• OS: Windows 11
• Browser Chrome
• Version 131.0.6778.205 (Official Build) (64-bit)

Ketcher version
[Version 3.1.0-rc.2]
Indigo version
[Version 1.29.0-rc.1]

Bug found while testing #6167