There exists a bug when Enable new post reactions menu is enabled, the left discourse-reactions-actions-x-left and discourse-reactions-reaction-button share the same component.
In mobile view, when long pressing the left discourse-reactions-actions-x-left, it triggers an unintended ReactionsPicker, which the console showing an error of Uncaught (in promise) TypeError: Cannot read properties of null (reading 'getBoundingClientRect') and a unresponsive picker panel.
This commit attach the event to element .discourse-reactions-reaction-button to prevent such things.