Link preview is shown outside from the closed CW

**Describe the bug** Link preview is shown outside from the closed CW so it's exposing people to content they would prefer to avoid. **To Reproduce** Steps to reproduce the behavior: 1. Write a post with a CW and add a link that can generate a preview. 2. See that the link preview is outside from the CW so it's visible. 3. Compare with Mastodon web interface: it's not visible but there is a link icon in the CW UI to know there is a link inside. **Expected behavior** The link preview should be hidden by default. **Versions** Pachli 3.6.0 **Affirmation** I have checked other issues for this project (open and closed) and I cannot find one that matches the problem I am reporting.