Error message on incorrect monomer index could be better

[AlexeyGirin]

Steps to Reproduce

1. Go to Macromolecules mode - Flex mode
2. Load using paste from clipboard IDT type: PEPTIDE1{A}|RNA1{R(A)P}$RNA1,PEPTIDE1,5:R2-1:R1$$$V2.0V2.0

Actual behavior System throws exception: Convert error! Given string could not be loaded as (query or plain) molecule or reaction, see the error messages: 'graph: can't have loop-edge on vertex 0' This is no informative.

Expected behavior System throws exception: Convert error! Given string could not be loaded as (query or plain) molecule or reaction, see the error messages: 'Monomer index (5) in polymer (RNA1) is not found'

Versions

• Ketcher Version 2.23.0-rc.1 Build at 2024-07-02; 08:57:41
• Indigo Toolkit Version 1.22.0-rc.1.0-g2bef0ce6c-wasm32-wasm-clang-19.0.0
• Windows 10 Pro
• Chrome Version 126.0.6478.127 (Official Build) (64-bit)

Issue found while testing - https://github.com/epam/Indigo/issues/1188

[AlexeyGirin]

Fixed.

• Ketcher Version 2.23.0-rc.3 Build at 2024-07-25; 05:30:25
• Indigo Toolkit Version 1.23.0-dev.1.14-g284c33a1-wasm32-wasm-clang-12.0.0
• Windows 10 Pro
• Chrome Version 127.0.6533.73 (Official Build) (64-bit)

[AlexeyGirin]

Fixed.

• Ketcher Version 2.23.0-rc.3 Build at 2024-07-31; 05:31:01
• Indigo Toolkit Version 1.23.0-dev.2.1-gd93b8ec4-wasm32-wasm-clang-12.0.0
• Windows 10 Pro
• Chrome Version 127.0.6533.89 (Official Build) (64-bit)