Add the InChI string as a property for all monomers

**Background**

This addition is introduced for the better/faster functioning of the [autorecognition feature](https://github.com/epam/ketcher/issues/8950) for monomers in the monomer creation wizard.

**Requirements**

- Every monomer should have the InChI string associated with its structure saved in the monomer file as a property of that monomer.
- The InChI string will not be visible to the user at any point.

Start by examining the monomer files used by the monomer creation wizard and the existing autorecognition work in issue #8950. Confirm how each monomer's structure is stored, then ensure every monomer carries an associated InChI property that is not exposed to users.

Written by the indexing model from the issue text.