Keep locked bones visible in Ghosting when deselected

The following change added in 4.3.17 made it possible to display bone ghosts:

> Added `Bones` setting for ghosting to draw bones.

So, for example, if you select and lock the “front-fist” bone on Spineboy, you can make it look like this:

However, even if the lock button is enabled in the Ghosting view while a specific bone is selected, that bone is no longer displayed after it is deselected when bone visibility is turned off in the viewport options:

When the lock button is enabled, it would be preferable for the bone to remain visible after it is deselected, even if bone visibility is disabled in the viewport options.

However, some visual distinction would be necessary to avoid giving the impression that the bone is still selected. The bone's appearance could be changed by adjusting its opacity or color. Ideally, similar to the display of attachments or motion vectors, the bone's color could be affected by the color configured for ghosting.

**Related forum thread:**
https://esotericsoftware.com/forum/d/30263-request-display-ghosted-bones

Reproduce the issue with the Spineboy example by selecting and locking a bone in the Ghosting view, then disabling bone visibility in the viewport options and deselecting it. Inspect the Ghosting and viewport visibility behavior; done means the locked ghosted bone remains visible while clearly distinguished from a selected bone, ideally using the configured ghosting color.

Written by the indexing model from the issue text.