Different text in error messages in standalone and remote mode when saving in InChi format

_Scenario 1_
**Steps to Reproduce**
1. Execute v2/indigo/convert
struct:
[struct.zip](https://github.com/epam/Indigo/files/6992059/struct.zip)
options: {smart-layout: true, ignore-stereochemistry-errors: true, mass-skip-error-on-pseudoatoms: false,…}
{
"smart-layout": true,
"ignore-stereochemistry-errors": true,
"mass-skip-error-on-pseudoatoms": false,
"gross-formula-add-rsites": true,
"gross-formula-add-isotopes": true
}
output_format: "chemical/x-inchi"

**Expected behavior**
Identical error messages in alert window.

**Actual behavior**
Remote mode: "IndigoException: core: is not a molecule"
Standalone mode: "core: is not a molecule"

The same behavior if InChi AuxInfo format:
output_format: "chemical/x-inchi-aux"

_Scenario 2_
**Steps to Reproduce**
1. Execute v2/indigo/convert
struct:
[rstruct.zip](https://github.com/epam/Indigo/files/6992119/rstruct.zip)
{
"smart-layout": true,
"ignore-stereochemistry-errors": true,
"mass-skip-error-on-pseudoatoms": false,
"gross-formula-add-rsites": true,
"gross-formula-add-isotopes": true
}
output_format: "chemical/x-inchi"

**Expected behavior**
Identical error messages in alert window.

**Actual behavior**
Remote mode: "IndigoException: inchi-wrapper: Molecule with RGroups cannot be converted into InChI"
Standalone mode: "inchi-wrapper: Molecule with RGroups cannot be converted into InChI"

The same behavior if InChi AuxInfo format:
output_format: "chemical/x-inchi-aux"

_Scenario 3_
**Steps to Reproduce**

1. Execute v2/indigo/convert
struct:
[ggroup.zip](https://github.com/epam/Indigo/files/6992136/ggroup.zip)
{
"smart-layout": true,
"ignore-stereochemistry-errors": true,
"mass-skip-error-on-pseudoatoms": false,
"gross-formula-add-rsites": true,
"gross-formula-add-isotopes": true
}
output_format: "chemical/x-inchi-aux"

**Expected behavior**
Identical error messages in alert window.

**Actual behavior**
Remote mode: "IndigoException: inchi-wrapper: Molecule with pseudoatom (xxx) cannot be converted into InChI"
Standalone mode: "inchi-wrapper: Molecule with pseudoatom (xxx) cannot be converted into InChI"

The same behavior if InChi AuxInfo format:
output_format: "chemical/x-inchi-aux"