Reagents: When opening the CML saved file with arrow and reagent, the arrow and the reagent disappear

**Steps to Reproduce**
1. Launch Ketcher
2. Create structure with arrow and reagent molecule above arrow
3. Save file as CML
4. Open saved file

**Expected behavior**
The file is displayed on the canvas as it was saved with no distortion of the structure.

**Actual behavior**
When opening the CML saved file with arrow and reagent, the arrow and the reagent disappear

**Attachments**

**Desktop (please complete the following information):**
- OS: Windows 10
- Browser Chrome
-
**Ketcher version**
[v2.7.0]
**Additional context**
Related Indigo issue: https://github.com/epam/Indigo/issues/933
Related requirements issue: https://github.com/epam/ketcher/issues/1711
#187700054

Reproduce the CML save-and-reopen workflow in Ketcher using an arrow and reagent molecule, then trace the corresponding CML handling in Indigo. Review the related Indigo issue #933 and Ketcher requirements issue #1711 first. Done means the reopened file preserves both the arrow and reagent without distorting the structure.

Written by the indexing model from the issue text.