Add a drag handle to the action bar

Description

When using slots, there are cases where the slot fits its height and width to the nested content, making it difficult to select and drag when it contains nested children since it wraps around them tightly.
Using dynamic padding in the editor can help, but it may cause the preview UI to feel disconnected from the actual rendered layout, leading users to design pages that look different when published.

To address this, we could consider adding a drag handle to the action bar so users can drag components by grabbing the handle.

Considerations

• Users can override the action bar, so we should probably expose the handle as an additional prop, similar to how the select parent action is handled.

Proposal

Add a drag handle icon to the action bar that allows users to drag and move the entire component.