[CLNP-7628] fix: read receipts not updating in real-time

[OnestarLee]

External Contributions

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If you have a pull request that you believe should be accepted, please contact
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and we'll evaluate if we can setup a CLA to allow for the contribution.

For Internal Contributors

[CLNP-7628](https://sendbird.atlassian.net/browse/CLNP-7628)

Description Of Changes

Message의 Read status가 실시간으로 변경되지 않은 문제 수정하였습니다.
MarkAsUnread 기능이 추가되면서 기존에 ChannelHandler의 이벤트가 변경되면서 발생한 문제입니다.
onUserMarkedRead, group_onUserMarkedUnread 이벤트 받을때 처리하도록 수정하였습니다

Types Of Changes

What types of changes does your code introduce to this project?
Put an x in the boxes that apply_

• Bugfix
• New feature
• Documentation (correction or otherwise)
• Cosmetics (whitespace, appearance (ex) Prettier)
• Build configuration
• Improvement (refactor code)
• Test

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 10.90%. Comparing base (231250c) to head (ad8eae1).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #267      +/-   ##
==========================================
+ Coverage   10.86%   10.90%   +0.04%     
==========================================
  Files         360      360              
  Lines        8999     9001       +2     
  Branches     2406     2407       +1     
==========================================
+ Hits          978      982       +4     
+ Misses       8020     8018       -2     
  Partials        1        1              

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