LinkControl: Add a state to the drawer button

[t-hamano]

What problem does this address?

The LinkControl component toggles the settings panel via a drawer button.

Personally, it is difficult to tell if a panel is open or not because the drawer button only changes color when the panel is opened.

What is your proposed solution?

How about adding a pressed state, similar to the opening and closing of the block sidebar and the document overview panel, or custom value entry in the block sidebar?

Make the icon smaller

I think that it would be better if the tooltip labels were also changed according to the state.

[t-hamano]

I am closing this issue because I have learned that the UI has been changed by #51712 and the drawer is gone.