Export the structure for nucleotides 5-Bromo dU does not work correctly

[AnnaKosol]

Steps to Reproduce

1. Go to Macromolecules mode - Flex mode
2. Load using paste from clipboard IDT type /55Br-dU//i5Br-dU//i5Br-dU//i5Br-dU//i5Br-dU/
   
   or create manually the following canvas:
   
3. Save canvas in the IDT format

Actual behavior

Expected behavior
Export should be /55Br-dU//i5Br-dU//i5Br-dU//i5Br-dU//i5Br-dU/

Versions:
Ketcher Version 2.23.0-rc.2 Build at 2024-07-10; 19:39:22
Indigo Version 1.22.0-rc.2.0-ga21fb5d8f-wasm32-wasm-clang-19.0.0
Chrome Версия 126.0.6478.127 (Официальная сборка), (arm64)
MacOs Sonoma 14.5

Issue found while testing - #4382

[AlexeyGirin]

Moved to indigo - epam/Indigo#2119