Update _index.md (#9138)

Removed the single binary from the scalability section as this is
confusing. This should be called monolithic also.

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

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

**Special notes for your reviewer**:

**Checklist**
- [ ] Reviewed the
[`CONTRIBUTING.md`](https://github.com/grafana/loki/blob/main/CONTRIBUTING.md)
guide (**required**)
- [ ] Documentation added
- [ ] Tests updated
- [ ] `CHANGELOG.md` updated
- [ ] Changes that require user attention or interaction to upgrade are
documented in `docs/sources/upgrading/_index.md`

docs/sources/fundamentals/overview/_index.md

@@ -56,9 +56,6 @@ and allows for efficient query execution.
 
 -  **Scalability**
 
-    Loki can be run as a single binary;
-    all the components run in one process.
-
     Loki is designed for scalability,
     as each of Loki's components can be run as microservices.
     Configuration permits scaling the microservices individually,