Ensure LLM summaries are normalized

[chiroptical]

Summary

Context: https://github.com/codeforboston/maple/pull/1948/files#r2471435426

We recognized some technical debt while working on the linked PR.

Work Detail

After that PR merges, we'll have normalize_summary and we'll need to use any place we generate summaries. Specifically, llm/bill_on_document_created.py and llm/main.py, look for summary["summary"].

We'll want to import from normalize_summaries import normalize_summary and run this normalization on generated summaries.

Checklist

1. Check to ensure this is not a duplicate ticket
2. Add the appropriate labels
3. Add the appropriate Zenhub Epic
4. If this a front-end dev ticket, ensure the relevant figma is linked