Coordinator is using 2 different logging wrappers on the same relation endpoint

### Enhancement Proposal

Currently, the coordinator is using `LokiPushApiConsumer` to pass the Loki endpoints to a worker that, which in turn, grabs those endpoints and forwards its logs using a [ManualLogForwarder](https://github.com/canonical/cos-coordinated-workers/blob/main/src/coordinated_workers/worker.py#L887).

Then, to forward the coordinator's own workload logs, we instantiate yet another logging wrapper `LogForwarder` on the same relation endpoint.

No issues were reported as a side-effect from this implementation (till now), but one side-effect is that each consumer class (`LokiPushApiConsumer` and `LogForwarder`) overwrites the same relation databag with the same set of alert rules causing unnecessary databag updates.

Proposal: Use `ManualLogForwarder` to forward the coordinator workload logs and avoid any databag updates that come with using `LogForwarder`.

Start in src/coordinated_workers/worker.py around the ManualLogForwarder definition at line 887, then trace the coordinator's LogForwarder setup and the LokiPushApiConsumer usage described in the issue. Replace the coordinator-side wrapper with the manual forwarder while preserving log forwarding and avoiding duplicate alert-rule databag updates; verify with the project's existing checks.

Written by the indexing model from the issue text.