An error appears when opening a reaction with R-group in the "MDL Rxnfile V3000" file format

**Steps to Reproduce**
1. Launch "Ketcher"
2. Open the Console
3. Draw any reaction with R-group on the canvas or open this file
[99.zip](https://github.com/epam/Indigo/files/12832606/99.zip)
4. Click on the "Save as" button
5. Select the "MDL Rxnfile V3000" file format
6. Click on the "Save" button
7. Open the saved file

**Expected behavior**
There is no error on the screen. The file opens

**Actual behavior**
The error appears on the screen. The file does not open (the same reaction in the "MDL Rxnfile V2000" file format opens)

**Attachments**

**Indigo/Bingo version**
1.14.0-rc.5.1

**Desktop (please complete the following information):**
• OS: Windows 10 Pro (version 22H2) x64
• Browser: Сhrome
• Version: (114.0.5735.199) x64