Copy/Paste of sense/antisense pair doesn't work

[AlexeyGirin]

Steps to Reproduce

1. Go to Macro - Sequence mode (clean canvas)
2. Load from HELM: RNA1{R(A)P.R(A)P.R(A)}|RNA2{R(U)P.R(U)}$RNA1,RNA2,8:pair-5:pair|RNA1,RNA2,2:pair-2:pair$$$V2.0
   
3. Click between A symbols to switch to Edit mode
   
4. Select sense-antisense pair and copy it to clipboard
   
5. Remove selection
   
6. Press Ctrl+V

Actual behavior
System throws exception: Paste of several fragments is prohibited in text-editing mode.

Expected behavior
System inserts selection from the clibboard

Versions

• Ketcher Version 3.1.0-rc.2 Build at 2025-02-07; 15:09:23
• Indigo Version 1.29.0-rc.1.0-g2e30df8f7-wasm32-wasm-clang-19.0.0
• Chrome Version 133.0.6943.54 (Official Build) (64-bit)
• Win10

Issue found while testing: #5942