[fix][broker] Fix incorrect unack msk count when dup ack a message

[Technoboy-]

Fixes #19268

Modifications

When pendingAck not contains the message, it means the msg has been removed, so it can't update the unack msg count..

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

[codecov-commenter]

Codecov Report

❌ Patch coverage is 72.72727% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 36.95%. Comparing base (63d9eaf) to head (fdac917).
⚠️ Report is 1771 commits behind head on master.

Files with missing lines	Patch %	Lines
...ava/org/apache/pulsar/broker/service/Consumer.java	72.72%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #20990      +/-   ##
============================================
+ Coverage     36.92%   36.95%   +0.02%     
- Complexity    12187    12229      +42     
============================================
  Files          1698     1698              
  Lines        129846   129857      +11     
  Branches      14163    14163              
============================================
+ Hits          47947    47986      +39     
+ Misses        75570    75548      -22     
+ Partials       6329     6323       -6     

Flag	Coverage Δ
inttests	24.29% <63.63%> (+0.14%)	⬆️
systests	25.18% <72.72%> (+0.02%)	⬆️
unittests	32.18% <63.63%> (+0.10%)	⬆️

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

Files with missing lines	Coverage Δ
...ava/org/apache/pulsar/broker/service/Consumer.java	63.47% <72.72%> (-1.09%)	⬇️

... and 59 files with indirect coverage changes

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[shibd]

@Technoboy- Can you help create a PR to cherry-pick this change to branch-2.11?