feat(stream search): serve regular methods through stream search

[forshev]

Description

• ComplexSearch and GetAggregation methods try to serve requests through stream search if request is suitable (no histogram, only one aggregation) and config flag is enabled.
• Support quantile and unique count aggregation functions in stream search

Fixes #498

---

• I have read and followed all requirements in CONTRIBUTING.md;
• I used LLM/AI assistance to make this pull request;

If you have used LLM/AI assistance please provide model name and full prompt:

Model: {{model-name}}
Prompt: {{prompt}}