[FIX] web: traceback in emoji picker

Before this commit:

- Attempting to press the Enter key in the emoji picker when the search result
  was empty would lead to a traceback error.

After this commit:

- Now, Pressing Enter key in the emoji picker with an empty search result no
  longer triggers a traceback error.

task-3576930

closes odoo/odoo#144434

X-original-commit: d9ea54fe8b3cf73da0e32155f2f08803ffe7440a
Signed-off-by: Geelen Sébastien (sge) <sge@odoo.com>

addons/web/static/src/core/emoji_picker/emoji_picker.js

@@ -286,7 +286,7 @@ export class EmojiPicker extends Component {
                     .querySelector(
                         `.o-EmojiPicker-content .o-Emoji[data-index="${this.state.activeEmojiIndex}"]`
                     )
-                    .click();
+                    ?.click();
                 break;
             case "Escape":
                 this.props.close?.();