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

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

Preset without name

```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> \nRNA\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):

> - `groupName` - string, mandatory. Used for preset name.
> Max length = 200, allowed symbols - no spaces, slashes minus @, # and so on

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

Start with the updateMonomersLibrary API call shown in the reproduction and trace how the monomerGroupTemplate input is validated. Reproduce the preset without groupName, then make the completed behavior report an error for the missing mandatory field and verify that valid presets still load.

Written by the indexing model from the issue text.