fix(docs): obsolete docs about rootless docker (#24376)

Description
-----------

The documentation lies about comments in `docker/docker-compose.dev.yml`.

Reason: in 689c6aa276 these docs were added
but the comments in this file are removed in
b9e2590752 and the docs weren't updated.

How Has This Been Tested?
-------------------------
```
$ git log -S rootless

commit b9e2590752
Author: Jason Rasmussen <jason@rasm.me>
Date:   Tue Sep 16 12:48:44 2025 -0400

    chore: simplify (#22082)

commit 689c6aa276
Author: Rudolf Horváth <R-Rudolf@users.noreply.github.com>
Date:   Thu Nov 21 13:25:45 2024 +0100

    docs: add developer notes about rootless docker setup (#13250)
```

Checklist:
----------

- [x] I have performed a self-review of my own code
- [x] I have made corresponding changes to the documentation if applicable
- [x] I have no unrelated changes in the PR.
- [ ] I have confirmed that any new dependencies are strictly necessary.
- [ ] I have written tests for new code (if applicable)
- [ ] I have followed naming conventions/patterns in the surrounding code
- [ ] All code in `src/services/` uses repositories implementations for database calls, filesystem operations, etc.
- [ ] All code in `src/repositories/` is pretty basic/simple and does not have any immich specific logic (that belongs in `src/services/`)

docs/docs/developer/setup.md

@@ -48,7 +48,6 @@ You can access the web from `http://your-machine-ip:3000` or `http://localhost:3
 **Notes:**
 
 - The "web" development container runs with uid 1000. If that uid does not have read/write permissions on the mounted volumes, you may encounter errors
-- In case of rootless docker setup, you need to use root within the container, otherwise you will encounter read/write permission related errors, see comments in `docker/docker-compose.dev.yml`.
 
 #### Connect web to a remote backend