Fix newly joined members not having ChannelReads

[b-onc]

Cases:

1. User A is watching the channel, non-member User B sends messageRead event
   -> We discard the event and log.debug it
2. User A is watching the channel, new member User B sends messageRead event
   -> We create a read event for User B, this is the fix introduced in this PR
3. User A is watching the channel, old member User B sends messageRead event
   -> Since User B is an old member, we received their read object when we queried the channel
4. User A is watching the channel and is not a member, User B sends a message
   -> User A doesn't have a read object until they re-query the channel (backend bug) or they join, we log.info the case
5. User A is watching the channel and is a new member, User B sends a message
   -> MemberEventMiddleware received the memberAdded event and re-queries the channel, creating a read object
   -> This is the only edge-edge case, before MemberEventMiddleware finishes creating the read object, all new messages cause the log.info log
6. User A is watching the channel and is an old member, User B sends a message
   -> Since User A is an old member, we received their read object when we queried the channel

[codecov]

Codecov Report

Merging #1068 (bf1c812) into main (0254fee) will increase coverage by 0.01%.
The diff coverage is 90.47%.

@@            Coverage Diff             @@
##             main    #1068      +/-   ##
==========================================
+ Coverage   91.04%   91.06%   +0.01%     
==========================================
  Files         215      215              
  Lines        8974     8994      +20     
==========================================
+ Hits         8170     8190      +20     
  Misses        804      804              

Flag	Coverage Δ
llc-tests	91.06% <90.47%> (+0.01%)	⬆️
llc-tests-ios12	91.06% <90.47%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
Sources/StreamChat/Database/DatabaseSession.swift	97.56% <ø> (ø)
...ventMiddlewares/ChannelReadUpdaterMiddleware.swift	95.00% <86.66%> (-0.66%)	⬇️
...rces/StreamChat/Database/DTOs/ChannelReadDTO.swift	100.00% <100.00%> (ø)
Sources/StreamChat/Deprecations.swift	20.00% <0.00%> (+20.00%)	⬆️

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[VojtaStavik]

Nice 👍

[VojtaStavik]

@b-onc can you add a changelog entry for this, please?