It is possible to create antisense even if it is not allowed (when base has extra bond out of r1-r3 to sugar)

[AlexeyGirin]

Steps to Reproduce

1. Go to Macro - Snake mode
2. Load from HELM using paste from clipboard: RNA1{R([nC6n5C])P.R([nC6n5C])P}$RNA1,RNA1,2:R2-5:R2$$$V2.0
   
3. Select all monomers on the top of the chain and click Create Antisense Strand from context menu
   

Actual behavior
System creates antisense chain for all bases

Expected behavior
Create Antisense Strand option is disabled

As per requirement:

1.2. If any of the bases connected to the sugars via R3-R1 have more bonds (hydrogen or covalent), the "Create Antisense Strand" option should appear, but be disabled.

Try the following case: RNA1{R([cl6pur])P.R([cl6pur])P}$$$$V2.0

Versions

• Ketcher Version 2.28.0-rc.1 Build at 2024-12-03; 17:04:52
• Indigo Version 1.27.0-rc.1.0-g8d656a341-wasm32-wasm-clang-19.0.0
• Chrome Version 131.0.6778.109 (Official Build) (64-bit)
• Win10

Issue found while testing - #5678

[SefaBilgii]

This issue is reproducible

Ketcher Version: 3.6.0-rc.1
OS: MacOs Sequoia Version 15.5
Browser : Chrome Version 138.0.7204.169
Indigo version 1.34.0-rc.1.0