Correcting spelling in list throws error

[launchargybargy]

📝 Provide detailed reproduction steps (if any)

1. Go to https://ckeditor.com/ckeditor-5/online-builder/
2. Select the Balloon editor
3. Click Remove all plugins
4. Find and add:

• List
• Liststyle
• Indent
• Font color

5. Click Next, add font color to the toolbar
6. Click Next Step x 2 to finish the wizard
7. Click Start
8. Extract the zip

Reproduction steps:

Open sample\index.html
Clear the text in the editor
Enter 'helllo', (with the incorrect spelling)
Select 'helllo' and make a bulleted list, and set a color.
Right click 'helllo', and select the suggested spelling of hello

✔️ Expected result

No errors, spelling corrected.

❌ Actual result

ckeditor.js:5 Uncaught TypeError: Cannot read property 'getStyle' of null
at um.t.on.priority (ckeditor.js:5)
at um.fire (ckeditor.js:5)
at um._convertItem (ckeditor.js:5)
at um.convert (ckeditor.js:5)
at Object.callback (ckeditor.js:5)
at eb._runPendingChanges (ckeditor.js:5)
at eb.change (ckeditor.js:5)
at bm.toModel (ckeditor.js:5)
at WC._handleContainerChildrenMutations (ckeditor.js:5)
at WC.handle (ckeditor.js:5)

📃 Other details

• Browser: 89.0.4389.90 (Official Build) (64-bit)
• OS: Windows 10 - 1909
• First affected CKEditor version: ckeditor5 v3
• Installed CKEditor plugins: list, liststyle, indent, fontColor

[FilipTokarski]

Hi, thanks for the report. I can confirm this. Here's a full stack trace:

Uncaught TypeError: Cannot read property 'getStyle' of null
    at UpcastDispatcher.dispatcher.on.priority (liststyleediting.js:215)
    at UpcastDispatcher.fire (emittermixin.js:194)
    at UpcastDispatcher._convertItem (upcastdispatcher.js:249)
    at UpcastDispatcher.convert (upcastdispatcher.js:207)
    at Object.callback (datacontroller.js:424)
    at Model._runPendingChanges (model.js:830)
    at Model.change (model.js:175)
    at DataController.toModel (datacontroller.js:423)
    at MutationHandler._handleContainerChildrenMutations (injecttypingmutationshandling.js:109)
    at MutationHandler.handle (injecttypingmutationshandling.js:64)

• it doesn't need to have FontColor plugin. It can be reproduced in any editor with ListStyle. Instead of font color you can just apply bold
• happens since the introduction of ListStyle