Export to SMARTS is invalid (unable to load back) for molecule with "star" atom with attachment points

**Steps to Reproduce**
1. Go to Molecules mode (empty canvas)
2. Load from KET: [molecule with star atom with attachment points.zip](https://github.com/user-attachments/files/21620671/molecule.with.star.atom.with.attachment.points.zip)

3. Save canvas to SMARTS

**Actual behavior**
Export result is invalid: `[*]1%91%92=[#6]-[*]%93=[#6]-[*]%94=[#6]-1`

**Expected behavior**
Export result should be loaded back correctly

**Environment details:**
- Ketcher Version 3.7.0-rc.1 Build at 2025-08-04; 22:44:37
- Indigo Version 1.35.0-rc.1.0-g1900fe55e-wasm32-wasm-clang-19.0.0
- Chrome Version 138.0.7204.97 (Official Build) (64-bit)
- Win10

Found while testing: https://github.com/epam/ketcher/issues/6150