[IMP] web_editor: remove dead '_onInput' code

The 'insertLineBreak' case in `onInput` is dead code because any event
that might cause it (pressing Shift+Enter) first triggers `onKeydown`,
which calls `ev.preventDefault()` and thus prevents it from reaching
`onInput`.

Task-3301232

closes odoo/odoo#121850

X-original-commit: c63cd2f0140959a7ac6e05ef15ac5c2ac552453d
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>

addons/web_editor/static/src/js/editor/odoo-editor/src/OdooEditor.js

@@ -3404,11 +3404,6 @@ export class OdooEditor extends EventTarget {
                     }
                 }
                 this.historyStep();
-            } else if (ev.inputType === 'insertLineBreak') {
-                this._compositionStep();
-                this.historyRollback();
-                ev.preventDefault();
-                this._applyCommand('oShiftEnter');
             } else {
                 this.historyStep();
             }