[BUG, important] Canvas links to notes are missing from metadata (sometimes)

[stdword]

Metadata cache is not properly displays backlinks to notes from canvases.

Demo:

canvas.links.mp4

Sometimes reloading of canvas fixes the issue. Sometimes it is not enough, and app reloading helps.
But the main problem: there is an illusion, that backlinks is always working, while they may be not.

Steps to reproduce:

1. Create some Note
2. Create some Canvas
3. Make text node in the Canvas with wiki-link to the Note
4. Quit the app and open it again
5. Make sure the Canvas is not opened and loaded
6. Open the Note
7. See empty backlinks list
8. Opening the canvas or reloading the app can fix the situation. But now I'v always cannot trust to backlinks list :(

[LexieSanders]

@Developer-Mike I have the same problem. Some of my pictures display canvas files in backlinks just fine. But several pictures display 0 backlinks despite being on a canvas

[Developer-Mike]

This is all in the same category as #245 #252. The metadata cache patches need to be updated completely I guess.