**What this PR does / why we need it**:

This PR allows user to enable tracing in the new SSD setup and fixes
incorrect documentation because it is currently impossible to enable
tracing in this chart (cf.
https://github.com/grafana/loki/blob/766f27645d2610a36eaaca8418482b740ae14215/cmd/loki/main.go#L81)

**Which issue(s) this PR fixes**:
Fixes #<issue number>

**Special notes for your reviewer**:

**Checklist**
- [x] Reviewed the
[`CONTRIBUTING.md`](https://github.com/grafana/loki/blob/main/CONTRIBUTING.md)
guide (**required**)
- [x] Documentation added
- [x] Tests updated
- [ ] `CHANGELOG.md` updated
- [ ] If the change is worth mentioning in the release notes, add
`add-to-release-notes` label
- [ ] Changes that require user attention or interaction to upgrade are
documented in `docs/sources/setup/upgrade/_index.md`
- [ ] For Helm chart changes bump the Helm chart version in
`production/helm/loki/Chart.yaml` and update
`production/helm/loki/CHANGELOG.md` and
`production/helm/loki/README.md`. [Example
PR](https://github.com/grafana/loki/commit/d10549e3ece02120974929894ee333d07755d213)
- [ ] If the change is deprecating or removing a configuration option,
update the `deprecated-config.yaml` and `deleted-config.yaml` files
respectively in the `tools/deprecated-config-checker` directory.
[Example
PR](https://github.com/grafana/loki/pull/10840/commits/0d4416a4b03739583349934b96f272fb4f685d15)

---------

Signed-off-by: QuentinBisson <quentin@giantswarm.io>