[FIX] EventNormalizer: consistently apply insertLineBreak on shift+enter

Prior to this fix, there were certain situations where doing shift+enter
was triggering an insertParagraph action instead of insertLineBreak. The
reason was that in those situations, the browser was actually giving an
insertText input type together with the "Enter" key, for some reason...

Steps to reproduce the fixed issue:
- open example Note "Project N.947.5" in Odoo
- add: Enter - couple of characters - Enter - couple of characters
- make the last line blockquote
- at the end of the last line, add: Shift+enter - couple of characters
- Shift+enter at this point broke the blockquote.

Author: Zynton

packages/plugin-dom-editable/src/EventNormalizer.ts

@@ -836,6 +836,7 @@ export class EventNormalizer {
             (cutEvent && 'deleteByCut') ||
             (dropEvent && 'insertFromDrop') ||
             (pasteEvent && 'insertFromPaste') ||
+            (key === 'Enter' && inputEvent?.inputType === 'insertText' && 'insertLineBreak') ||
             (inputEvent && inputEvent.inputType);
 
         // In case of accent inserted from a Mac, check that the char before was