Open sidebar menu entry is gone in main branch

[max-nextcloud]

Describe the bug
When opening a text file in the viewer the menu entry for opening the sidebar is gone.

First showed up in texts playwrigth tests

To Reproduce
Steps to reproduce the behavior:

1. Use the latest server and viewer master branches
2. Open a text file.
3. Click on the three dot menu
4. See no menu entry to open sidebar

Expected behavior
Allow opening the sidebar from the viewer so versions can be listed and compared.

Screenshots

[susnux]

Needs some debugging, with Nextcloud 33 its required to have enableSidebar set on the Viewer open call (but its enabled by default so should already be the case).

[max-nextcloud]

Looks like this.Sidebar is not initialized.

[susnux]

Yes because that does not exist anymore. Creating a PR.