fix(previews): sidebar message previews fix for sent attachments

[Jekrimo]

What this PR does 📖

• Added a comparative to check against last_message_id where if there isn't one we show "No messages sent yet." and if there is but last_message_preview is "" then we show "New Attachement", otherwise show the last message

Which issue(s) this PR fixes 🔨

• Resolve bug(chat): "No messages sent yet" in sidebar when sending attachments  #319

Special notes for reviewers 🗒️

Additional comments 🎤

I think if we could get some extra properties onto our Message types we could clean some of the logic up but from what I understand that would take some extra Warp magic that I don't understand

[github-actions]

Automated Test Results

 119 passed
 1 flaky
 4 skipped

Details

 124 tests across 16 suites
 18 minutes, 56 seconds
 fc84471

Flaky tests

Automated Tests on Chrome Desktop › 03-friends-two-instances.spec.ts › Two instances tests - Friends and Chats › B7, B57, B58 - Favorites tests

Skipped tests

Automated Tests on Chrome Desktop › 03-friends-two-instances.spec.ts › Two instances tests - Friends and Chats › B8 to B14 - Quick Profile Local and Remote - Updating note
Automated Tests on Chrome Desktop › 03-friends-two-instances.spec.ts › Two instances tests - Friends and Chats › B8 to B14 - Quick Profile Local - Updating username, status, banner and profile picture
Automated Tests on Chrome Desktop › 03-friends-two-instances.spec.ts › Two instances tests - Friends and Chats › B8 to B14 - Quick Profile Remote - Updating username, status, banner and profile picture
Automated Tests on Chrome Desktop › 20-settings-developer.spec.ts › Settings Developer Tests › T4 - Clicking Clear State should clear users state

[github-actions]

Playwright test execution is complete! You can find the test results report here