Allow to pin any message

[testableapple]

🔗 Issue Links

Resolve https://github.com/GetStream/ios-issues-tracking/issues/782

🎯 Goal

Allow to pin any message

📝 Summary

• Replace update with partial update on pinning the message
• Update DemoApp pinning logic

🎨 Showcase

🧪 Manual Testing Notes

1. Pin the current user's message

2. Pin the participant's message

3. Login as a participant => Verify that messages are pinned with correct labels

4. Unpin the current user's message

5. Unpin the participant's message

6. Login as a participant => Verify that messages are unpinned

☑️ Contributor Checklist

• [x] I have signed the Stream CLA (required)
• [x] This change follows zero ⚠️ policy (required)
• [x] This change should be manually QAed
• [ ] Changelog is updated with client-facing changes
• [ ] New code is covered by unit tests
• [ ] Comparison screenshots added for visual changes
• [ ] Affected documentation updated (docusaurus, tutorial, CMS)

🎁 Meme

[Stream-iOS-Bot]

StreamChat XCMetrics

target	metric	benchmark	branch	performance	status
MessageList	Hitches total duration	10 ms	8.34 ms	16.6% 🔼	🟢
	Duration	2.6 s	2.55 s	1.92% 🔼	🟢
	Hitch time ratio	4 ms per s	3.28 ms per s	18.0% 🔼	🟢
	Frame rate	79 fps	78.21 fps	1.0% 🔼	🟢
	Number of hitches	1	0.6	40.0% 🔼	🟢
ChannelList	Hitches total duration	12.5 ms	2.5 ms	80.0% 🔼	🟢
	Duration	2.6 s	0.82 s	68.46% 🔼	🟢
	Hitch time ratio	5 ms per s	3.03 ms per s	39.4% 🔼	🟢
	Frame rate	76 fps	63.75 fps	16.12% 🔼	🟢
	Number of hitches	1.2	0.2	83.33% 🔼	🟢

[sonarcloud[bot]]

Quality Gate passed

Issues
66 New issues
0 Accepted issues

Measures
0 Security Hotspots
83.8% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud