Render action: saving structures as .svg and as .png incorrectly

_Scenario 1_
When structure has Generic S-Group, saved structure does not have brackets
**Steps to reproduce:**
1. Execute /v2/indigo/render
struct
[sstruct.zip](https://github.com/epam/Indigo/files/6992488/sstruct.zip)
{
"smart-layout": true,
"ignore-stereochemistry-errors": true,
"mass-skip-error-on-pseudoatoms": false,
"gross-formula-add-rsites": true,
"render-output-format": "png"
}

**Expected result:**
The same structure as in sstruct.zip

**Actual result:**
Structure without brackets

_Scenario 2_
Structure with R-group is not saved
**Steps to reproduce:**
1. Execute /v2/indigo/render
struct
[rstruct.zip](https://github.com/epam/Indigo/files/6992557/rstruct.zip)
{
"smart-layout": true,
"ignore-stereochemistry-errors": true,
"mass-skip-error-on-pseudoatoms": false,
"gross-formula-add-rsites": true,
"render-output-format": "svg"
}

**Expected result:**
The same structure as in rstruct.zip

**Actual result:**
Structure is not saved, empty document.

_Scenario 3_
Saved bonds does not have Reacting Center marks.

**Steps to reproduce:**
1. Execute /v2/indigo/render
struct
[rcstruct.zip](https://github.com/epam/Indigo/files/6992729/rcstruct.zip)
{
"smart-layout": true,
"ignore-stereochemistry-errors": true,
"mass-skip-error-on-pseudoatoms": false,
"gross-formula-add-rsites": true,
"render-output-format": "svg"
}

**Expected result:**
The same structure as in rcstruct.zip

**Actual result:**
Structure without reacting centers

_Scenario 4_
When inversion type is chosen in the atom's properties, it is not saved.

**Steps to reproduce:**
1. Execute /v2/indigo/render
struct:
[istruct.zip](https://github.com/epam/Indigo/files/6992780/istruct.zip)
{
"smart-layout": true,
"ignore-stereochemistry-errors": true,
"mass-skip-error-on-pseudoatoms": false,
"gross-formula-add-rsites": true,
"render-output-format": "svg"
}

**Expected result:**
The same structure as in istruct.zip

**Actual result:**
Structure without Inv property

_Scenario 5_
Structure with R-group saved without brackets
**Steps to reproduce:**
1. Execute /v2/indigo/render
struct:
[bstruct.zip](https://github.com/epam/Indigo/files/6993059/bstruct.zip)

{
"smart-layout": true,
"ignore-stereochemistry-errors": true,
"mass-skip-error-on-pseudoatoms": false,
"gross-formula-add-rsites": true,
"render-output-format": "svg"
}

**Expected result:**
The same structure as in bstruct.zip

**Actual result:**
Structure without brackets

All applied to "render-output-format": "svg" and "png" both