theme(fix): share link building when `params` particle is present (#769)

In these cases the site permalink is used instead of the social network
URL for sharing as defined in the `link` value
(https://www.linkedin.com/shareArticle in the below example)

Most visible case is LinkedIn but all social networks that have

```toml
[ananke.social.networks.particles]
...
params = "..."
```

in `config/_default/params.toml` are affected by this bug.

Closes #768.