LinkControl: Remove tools controls from initial state

[richtabor]

Part of #50891

The link settings, cancel, and apply "tools" (block-editor-link-control__tools) should only available when a link has been applied—not before. Let's remove these controls and have them only render if a link is added to the control.

Current	Proposed

[getdave]

This suggestion feels right when yuo consider the UX as a whole as outlined in #50891.

My only concern remains that this may make it difficult for users of assistive technology to dismiss the popover (we cannot rely on Esc as many users won't know about this convention).

I'm not suggesting we retain Apply/Cancel but rather we consider

• adding a dedicated close X
• work with a11y team to see if a visually hidden Close button might be an appropriate compromise

[richtabor]

My only concern remains that this may make it difficult for users of assistive technology to dismiss the popover (we cannot rely on Esc as many users won't know about this convention).

I'm fairly confident there's not a dedicated close action on any other popover, and I don't think LinkControl should be treated any differently. Also, ESC does work within the popovers throughout the editor — so I would think the convention would be realized.

[richtabor]

retain Apply/Cancel

I do think it's good to keep Apply and Cancel actions within the context of editing a link #50890 — as it affords understanding to whether or not link changes have been saved, or discarded.

[getdave]

Good to know we've considered this and accounted for the tradeoffs 👍

[richtabor]

This was done as part of #51712