fix(blooms): Skip multi-tenant TSDBs during bloom planning (backport k227)

[loki-gh-app]

Backport 76d35cc from #14770

---

What this PR does / why we need it:
Tables that have not been fully compacted yet will have multi-tenant TSDBs for which the tenant is "" (coming tsdbStore.UsersForPeriod and indexStorageClient.ListFiles)

In this PR we update the planner to skip these multi-tenant TSDBs.

I though about fixing this at the indexStorageClient.ListFiles level but I think it's relatively risky given it's is used in the compactor.

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