🗂️ fix: Optimize Conversation Grouping and Sorting

[danny-avila]

Summary

Closes #4160

• Refactored the groupConversationsByDate function to use Maps for better performance and readability.
• Implemented a custom sorting algorithm for year/month groups to ensure chronological order instead of alphabetical.
• Added a monthOrderMap to facilitate correct sorting of months within years.
• Optimized the sorting of conversations within each group to be more efficient.
• Added a new test case in convos.spec.ts to verify correct month sorting behavior.
• Fixed ESLint warnings in convos.ts by improving null checks and using nullish coalescing operators.

Other Changes

• Removed a duplicate import of TrashIcon in VectorStoreListItem.tsx.

Checklist

• [x] My code adheres to this project's style guidelines
• [x] I have performed a self-review of my own code
• [x] I have commented in any complex areas of my code
• [x] I have made pertinent documentation changes
• [x] My changes do not introduce new warnings
• [x] I have written tests demonstrating that my changes are effective or that my feature works
• [x] Local unit tests pass with my changes

Before

After

[fuegovic]

Older conversations from 2023 are still not properly organized, even with this fix. To be honest, I'm not sure where they are now.

Edit: It appears they are at the end; I believe only the separator for the previous year section is missing.

[danny-avila]

Odd thanks for letting me know @fuegovic

[danny-avila]

@fuegovic they are actually being grouped correctly but a typing issue is causing this, fixing this with some added tests