Expose dropdown open/close events to allow external scroll locking

[expiante]

Currently, it is not possible to track whether an editor dropdown (e.g. suggestion menu, formatting menu) is open from outside the editor.

This makes it difficult to prevent background scrolling, especially in layouts where the editor is placed inside a custom scrollable container rather than relying on document.body.

Expected Behavior

• A callback or event when an editor dropdown opens or closes
• Allow consumers to:
  • Disable scrolling on their own scrollable container
  • Re-enable scrolling when the dropdown is closed

This would make dropdown interactions easier and more predictable in complex layouts.

[nperez0111]

Will require some thought on how we approach this, I'd prefer to have better defaults but would need to review our dropdown usage to see if there is a rule we can apply to all of them

[woutervroege]

Referencing #1403

[woutervroege]

Not convinced this should be user controllable. Tend to think scroll jumping is a UX concern that should be avoided in every instance at all costs.