Migrate the thread responses to the generated thread models

[gpunto]

Goal

Parse the thread responses, and the threads embedded in read and thread events, with the generated models.

Part of AND-1291

Stacked on #6751.

Implementation

• queryThreads, getThread and partialUpdateThread return the generated QueryThreadsResponse, GetThreadResponse and UpdateThreadPartialResponse. Their threads are the generated ThreadStateResponse and ThreadResponse, with read adapters that collect the thread's custom data.
• The thread in message.read, notification.mark_read and thread.updated is the generated ThreadResponse.
• A thread without a parent message or a last message date fails the call, as a thread missing those fields failed to parse before.
• Delete the hand-written thread DTOs, their adapters and the two response wrappers.

Testing

Thread parsing tests run on the generated models, and the mapping tests cover a thread that cannot be mapped.

On a device, with a thread that has replies, a custom field and a draft: the partial update response, thread.updated, queryThreads, getThread and the thread in message.read returned the expected parent message, creator, counts, participants, latest replies, read state, title, custom field and draft.

🤖 Generated with Claude Code

[github-actions]

PR checklist ✅

All required conditions are satisfied:

• Title length is OK (or ignored by label).
• At least one pr: label exists.
• Sections ### Goal, ### Implementation, and ### Testing are filled, or the PR is bot-authored.
• An issue is linked (Linear ticket or GitHub issue), or the PR is bot-authored.

🎉 Great job! This PR is ready for review.

[github-actions]

SDK Size Comparison 📏

SDK	Before	After	Difference	Status
stream-chat-android-client	6.13 MB	6.14 MB	0.00 MB	🟢
stream-chat-android-ui-components	11.43 MB	11.43 MB	0.00 MB	🟢
stream-chat-android-compose	13.11 MB	13.11 MB	-0.00 MB	🚀

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
84.7% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud