No error if preset loaded to the library without <groupClass> defined

**Steps to Reproduce**
1. Open Macromolecules - Flex mode (clean canvas)
2. Go to console and execute following commands:

Preset without groupClass

```javascript
await ketcher.updateMonomersLibrary('\n -INDIGO-10092514292D\n\n 0 0 0 0 0 0 0 0 0 0 0 V3000\nM V30 BEGIN CTAB\nM V30 COUNTS 3 2 0 0 0\nM V30 BEGIN ATOM\nM V30 1 Base1 7.7 -8.025 0.0 0 CLASS=BASE SEQID=1 ATTCHORD=(2 3 Al)\nM V30 2 Phosphate1 9.2 -6.525 0.0 0 CLASS=PHOSPHATE SEQID=1 ATTCHORD=(2 3 Al-\nM V30 )\nM V30 3 Sugar1 7.7 -6.525 0.0 0 CLASS=SUGAR SEQID=1 ATTCHORD=(4 1 Cx 2 Br)\nM V30 END ATOM\nM V30 BEGIN BOND\nM V30 1 1 3 1\nM V30 2 1 3 2\nM V30 END BOND\nM V30 END CTAB\nM V30 BEGIN TEMPLATE\nM V30 TEMPLATE 1 BASE/Base1/Base1 NATREPLACE=BASE/U\nM V30 BEGIN CTAB\nM V30 COUNTS 13 12 5 0 0\nM V30 BEGIN ATOM\nM V30 1 H -4.33 0.75 0.0 0\nM V30 2 C -3.464 0.25 0.0 0\nM V30 3 C -2.598 0.75 0.0 0\nM V30 4 C -1.732 0.25 0.0 0\nM V30 5 C -0.866 0.75 0.0 0\nM V30 6 C 0.0 0.25 0.0 0\nM V30 7 C 0.866 0.75 0.0 0\nM V30 8 C 1.732 0.25 0.0 0\nM V30 9 C 2.598 0.75 0.0 0\nM V30 10 C 3.464 0.25 0.0 0\nM V30 11 H 4.33 0.75 0.0 0\nM V30 12 H -3.464 -0.75 0.0 0\nM V30 13 H -1.732 -0.75 0.0 0\nM V30 END ATOM\nM V30 BEGIN BOND\nM V30 1 1 1 2\nM V30 2 1 2 3\nM V30 3 1 3 4\nM V30 4 1 4 5\nM V30 5 1 5 6\nM V30 6 1 6 7\nM V30 7 1 7 8\nM V30 8 1 8 9\nM V30 9 1 9 10\nM V30 10 1 10 11\nM V30 11 1 2 12\nM V30 12 1 4 13\nM V30 END BOND\nM V30 BEGIN SGROUP\nM V30 1 SUP 1 ATOMS=(1 1) XBONDS=(1 1) BRKXYZ=(9 0.433000 -0.250000 0.000000-\nM V30 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) LABEL=H CLASS=-\nM V30 LGRP\nM V30 2 SUP 2 ATOMS=(1 11) XBONDS=(1 10) BRKXYZ=(9 -0.433000 -0.250000 0.000-\nM V30 000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) LABEL=H CLA-\nM V30 SS=LGRP\nM V30 3 SUP 3 ATOMS=(1 12) XBONDS=(1 11) BRKXYZ=(9 0.000000 0.500000 0.00000-\nM V30 0 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) LABEL=H CLASS-\nM V30 =LGRP\nM V30 4 SUP 4 ATOMS=(1 13) XBONDS=(1 12) BRKXYZ=(9 0.000000 0.500000 0.00000-\nM V30 0 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) LABEL=H CLASS-\nM V30 =LGRP\nM V30 5 SUP 5 ATOMS=(9 2 3 4 5 6 7 8 9 10) XBONDS=(4 1 11 12 10) BRKXYZ=(9 --\nM V30 0.433000 0.250000 0.000000 0.000000 -0.500000 0.000000 0.000000 0.0000-\nM V30 00 0.000000) BRKXYZ=(9 0.000000 -0.500000 0.000000 0.433000 0.250000 0-\nM V30 .000000 0.000000 0.000000 0.000000) LABEL=Base1 CLASS=BASE SAP=(3 2 1 -\nM V30 Al) SAP=(3 10 11 Br) SAP=(3 2 12 Cx) SAP=(3 4 13 Dx) NATREPLACE=BASE/U\nM V30 END SGROUP\nM V30 END CTAB\nM V30 TEMPLATE 2 PHOSPHATE/Phosphate1/Phosphate1 NATREPLACE=PHOSPHATE/P\nM V30 BEGIN CTAB\nM V30 COUNTS 16 15 6 0 0\nM V30 BEGIN ATOM\nM V30 1 H -5.196 0.75 0.0 0\nM V30 2 C -4.33 0.25 0.0 0\nM V30 3 C -3.464 0.75 0.0 0\nM V30 4 C -2.598 0.25 0.0 0\nM V30 5 C -1.732 0.75 0.0 0\nM V30 6 C -0.866 0.25 0.0 0\nM V30 7 C 0.0 0.75 0.0 0\nM V30 8 C 0.866 0.25 0.0 0\nM V30 9 C 1.732 0.75 0.0 0\nM V30 10 C 2.598 0.25 0.0 0\nM V30 11 C 3.464 0.75 0.0 0\nM V30 12 C 4.33 0.25 0.0 0\nM V30 13 H 5.196 0.75 0.0 0\nM V30 14 H -4.33 -0.75 0.0 0\nM V30 15 H -2.598 -0.75 0.0 0\nM V30 16 H -0.866 -0.75 0.0 0\nM V30 END ATOM\nM V30 BEGIN BOND\nM V30 1 1 1 2\nM V30 2 1 2 3\nM V30 3 1 3 4\nM V30 4 1 4 5\nM V30 5 1 5 6\nM V30 6 1 6 7\nM V30 7 1 7 8\nM V30 8 1 8 9\nM V30 9 1 9 10\nM V30 10 1 10 11\nM V30 11 1 11 12\nM V30 12 1 12 13\nM V30 13 1 2 14\nM V30 14 1 4 15\nM V30 15 1 6 16\nM V30 END BOND\nM V30 BEGIN SGROUP\nM V30 1 SUP 1 ATOMS=(1 1) XBONDS=(1 1) BRKXYZ=(9 0.433000 -0.250000 0.000000-\nM V30 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) LABEL=H CLASS=-\nM V30 LGRP\nM V30 2 SUP 2 ATOMS=(1 13) XBONDS=(1 12) BRKXYZ=(9 -0.433000 -0.250000 0.000-\nM V30 000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) LABEL=H CLA-\nM V30 SS=LGRP\nM V30 3 SUP 3 ATOMS=(1 14) XBONDS=(1 13) BRKXYZ=(9 0.000000 0.500000 0.00000-\nM V30 0 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) LABEL=H CLASS-\nM V30 =LGRP\nM V30 4 SUP 4 ATOMS=(1 15) XBONDS=(1 14) BRKXYZ=(9 0.000000 0.500000 0.00000-\nM V30 0 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) LABEL=H CLASS-\nM V30 =LGRP\nM V30 5 SUP 5 ATOMS=(1 16) XBONDS=(1 15) BRKXYZ=(9 0.000000 0.500000 0.00000-\nM V30 0 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) LABEL=H CLASS-\nM V30 =LGRP\nM V30 6 SUP 6 ATOMS=(11 2 3 4 5 6 7 8 9 10 11 12) XBONDS=(5 1 13 14 15 12) B-\nM V30 RKXYZ=(9 -0.433000 0.250000 0.000000 0.000000 -0.500000 0.000000 0.000-\nM V30 000 0.000000 0.000000) BRKXYZ=(9 0.000000 -0.500000 0.000000 0.000000 -\nM V30 -0.500000 0.000000 0.000000 0.000000 0.000000) BRKXYZ=(9 0.433000 0.25-\nM V30 0000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) L-\nM V30 ABEL=Phosphate1 CLASS=PHOSPHATE SAP=(3 2 1 Al) SAP=(3 12 13 Br) SAP=(3-\nM V30 2 14 Cx) SAP=(3 4 15 Dx) SAP=(3 6 16 Ex) NATREPLACE=PHOSPHATE/P\nM V30 END SGROUP\nM V30 END CTAB\nM V30 TEMPLATE 3 SUGAR/Sugar1/Sugar1 NATREPLACE=SUGAR/R\nM V30 BEGIN CTAB\nM V30 COUNTS 14 13 4 0 0\nM V30 BEGIN ATOM\nM V30 1 H -5.196 0.75 0.0 0\nM V30 2 C -4.33 0.25 0.0 0\nM V30 3 C -3.464 0.75 0.0 0\nM V30 4 C -2.598 0.25 0.0 0\nM V30 5 C -1.732 0.75 0.0 0\nM V30 6 C -0.866 0.25 0.0 0\nM V30 7 C 0.0 0.75 0.0 0\nM V30 8 C 0.866 0.25 0.0 0\nM V30 9 C 1.732 0.75 0.0 0\nM V30 10 C 2.598 0.25 0.0 0\nM V30 11 C 3.464 0.75 0.0 0\nM V30 12 C 4.33 0.25 0.0 0\nM V30 13 H 5.196 0.75 0.0 0\nM V30 14 H -4.33 -0.75 0.0 0\nM V30 END ATOM\nM V30 BEGIN BOND\nM V30 1 1 1 2\nM V30 2 1 2 3\nM V30 3 1 3 4\nM V30 4 1 4 5\nM V30 5 1 5 6\nM V30 6 1 6 7\nM V30 7 1 7 8\nM V30 8 1 8 9\nM V30 9 1 9 10\nM V30 10 1 10 11\nM V30 11 1 11 12\nM V30 12 1 12 13\nM V30 13 1 2 14\nM V30 END BOND\nM V30 BEGIN SGROUP\nM V30 1 SUP 1 ATOMS=(1 1) XBONDS=(1 1) BRKXYZ=(9 0.433000 -0.250000 0.000000-\nM V30 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) LABEL=H CLASS=-\nM V30 LGRP\nM V30 2 SUP 2 ATOMS=(1 13) XBONDS=(1 12) BRKXYZ=(9 -0.433000 -0.250000 0.000-\nM V30 000 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) LABEL=H CLA-\nM V30 SS=LGRP\nM V30 3 SUP 3 ATOMS=(1 14) XBONDS=(1 13) BRKXYZ=(9 0.000000 0.500000 0.00000-\nM V30 0 0.000000 0.000000 0.000000 0.000000 0.000000 0.000000) LABEL=H CLASS-\nM V30 =LGRP\nM V30 4 SUP 4 ATOMS=(11 2 3 4 5 6 7 8 9 10 11 12) XBONDS=(3 1 13 12) BRKXYZ=-\nM V30 (9 -0.433000 0.250000 0.000000 0.000000 -0.500000 0.000000 0.000000 0.-\nM V30 000000 0.000000) BRKXYZ=(9 0.433000 0.250000 0.000000 0.000000 0.00000-\nM V30 0 0.000000 0.000000 0.000000 0.000000) LABEL=Sugar1 CLASS=SUGAR SAP=(3-\nM V30 2 1 Al) SAP=(3 12 13 Br) SAP=(3 2 14 Cx) NATREPLACE=SUGAR/R\nM V30 END SGROUP\nM V30 END CTAB\nM V30 END TEMPLATE\nM END\n> \nmonomerGroupTemplate\n\n> \n_A1\n\n> \nbase=r_A1\n\n$$$$\n', { format: 'sdf' })
```

**Actual behavior**
No preset appears in the library, no error in the console

**Expected behavior**
System should throw error in console

As per [requirement](https://github.com/epam/Indigo/issues/3161):

> - `groupClass` - mandatory. Possible values: `RNA`

and per @ljubica-milovic :

**Environment details:**
- Ketcher Version 3.9.0-rc.1 Build at 2025-10-02; 16:35:40
- Indigo Version 1.37.0-rc.1.0-gca09660df-wasm32-wasm-clang-19.0.0
- Chrome Version 141.0.7390.55 (Official Build) (64-bit)
- Win10

Related issue: https://github.com/epam/Indigo/issues/3161

Reproduce the issue in Macromolecules - Flex mode using the supplied JavaScript updateMonomersLibrary call and SDF preset, then trace the validation path for monomerGroupTemplate. Compare the mandatory groupClass requirement in related issue #3161. Done means a preset without groupClass is rejected and an error appears in the console.

Written by the indexing model from the issue text.