Cursor State Tracking bug

[ashfame]

If we highlight some text in a paragraph block, depending on where you release the mouse button, the window.wp?.data?.select('core/block-editor').getSelectionEnd() call can not have the offset property in it.

For cursor state tracking, we need to assume the offset to max value in such a case.

[ashfame]

Additionally, with #8 there is another issue where sometimes despite making a selection, the right cursor position is not broadcasted (last known is broadcasted and state is updated again I suspect), so it seems like the state in the other browser is lagging behind by one additional sync.