[FEATURE] Support top N log pattern in summary context provider

[songkant-aws]

Is your feature request related to a problem?
When an alert is triggered, sometimes it's useful to analyze suspicious log data with common patterns. Using additional ppl queries to fetch log patterns could help triage the issue and we can leverage llm to summarize and discover potential issues.

What solution would you like?
Use default log pattern ppl query to find common patterns of longest text error log.

Do you have any additional context?

[dblock]

[Catch All Triage - 1, 2]