Fix marking channel read after leaving channel view

[nuno-vieira]

🔗 Issue Links

Resolves https://github.com/GetStream/ios-issues-tracking/issues/777
Related to #3089

🎯 Goal

Fix marking a channel read even after the user has left the channel view.

📝 Summary

This could happen in a case where the user left the channel view, but the debouncer would still trigger a request to markRead.

🛠 Implementation

Now, when the user leaves the channel view, we cancel the throttler.

🧪 Manual Testing Notes

Follow steps of #3089

☑️ Contributor Checklist

• I have signed the Stream CLA (required)
• This change follows zero ⚠️ policy (required)
• 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)

[Stream-iOS-Bot]

StreamChat XCMetrics

target	metric	benchmark	branch	performance	status
MessageList	Hitches total duration	10 ms	5.01 ms	49.9% 🔼	🟢
	Duration	2.6 s	2.54 s	2.31% 🔼	🟢
	Hitch time ratio	4 ms per s	1.96 ms per s	51.0% 🔼	🟢
	Frame rate	79 fps	78.14 fps	1.09% 🔼	🟢
	Number of hitches	1	0.4	60.0% 🔼	🟢
ChannelList	Hitches total duration	12.5 ms	21.69 ms	-73.52% 🔽	🔴
	Duration	2.6 s	2.54 s	2.31% 🔼	🟢
	Hitch time ratio	5 ms per s	8.55 ms per s	-71.0% 🔽	🔴
	Frame rate	76 fps	73.92 fps	2.74% 🔼	🟢
	Number of hitches	1.2	1.6	-33.33% 🔽	🔴

[sonarcloud]

Quality Gate passed

Issues
68 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

[laevandus]

Verified it manually