feat: hide __aggregated_metric__ in /series and /labels

[trevorwhitney]

What this PR does / why we need it:

This PR removes {__aggregated_metric=~".+"} streams from the /series endpoint, unless an __aggregated_metric__ matcher is explicitly requested. It does the same for /labels, so __aggregated_metric__ will not appear in a /labels response, but you can still request /labels/__aggregated_metric/values.

This will alleviate confusion for people using a tool like logcli series --analyze-labels for cardinatlity analysis.

Special notes for your reviewer:

Checklist

• [ ] Reviewed the CONTRIBUTING.md guide (required)
• [ ] Documentation added
• [ ] Tests updated
• [ ] Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.
• [ ] Changes that require user attention or interaction to upgrade are documented in docs/sources/setup/upgrade/_index.md
• [ ] 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

[trevorwhitney]

I'm closing this for now, we'll see if we want it again in the future