[FIX] web_editor: command prompt not displaying on focus

Before this commit:

command prompt is not displayed when html field has placeholder.

After this commit:

placeholder is replaced with command prompt when focused.

Task-2881079

closes odoo/odoo#108175

X-original-commit: 16cb4af921fec5483e366ea0a1b402631a7e28f3
Signed-off-by: David Monjoie (dmo) <dmo@odoo.com>

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

@@ -3829,7 +3829,8 @@ export class OdooEditor extends EventTarget {
         }
 
         // placeholder hint
-        if (this.editable.textContent === '' && this.options.placeholder && this.editable.firstChild && this.editable.firstChild.innerHTML) {
+        const sel = this.document.getSelection();
+        if (this.editable.textContent.trim() === '' && this.options.placeholder && this.editable.firstChild && this.editable.firstChild.innerHTML && !this.editable.contains(sel.focusNode)) {
             this._makeHint(this.editable.firstChild, this.options.placeholder, true);
         }
     }