Incomplete, maybe corrupted, styler (theme) xml can cause Npp to crash.

Steps to Reproduce the Issue

1. Edit stylers.xml or any theme.xml and add the following line <LexerType name="aaa" desc="aaa" ext="" />
2. Start Npp
3. Chose Settings->Style Configurator
4. Select aaa from the Language combobox

Expected Behavior

no crash

Actual Behavior

crash

Debug Information

I assume this happens with older releases as well but tested with

Notepad++ v8.4.5 (32-bit)
Build time : Sep 3 2022 - 03:56:37
Path : D:\temp\delete\notepad++.exe
Command Line :
Admin mode : OFF
Local Conf mode : ON
Cloud Config : OFF
OS Name : Windows 10 Enterprise (64-bit)
OS Version : 21H2
OS Build : 19044.1889
Current ANSI codepage : 1252
Plugins :
mimeTools (2.8)
NppConverter (4.4)
NppExport (0.4)