[fix][broker] Fix incorrect number of read compacted entries

[coderzc]

Motivation

Currently, the number of read compacted entries is wrong, which is one more than the specified number.

Modifications

Fix incorrect number of read compacted entries.

Verifying this change

• Make sure that the change passes the CI checks.

(Please pick either of the following options)

This change is a trivial rework / code cleanup without any test coverage.

(or)

This change is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

(example:)

• Added integration tests for end-to-end deployment with large payloads (10MB)
• Extended integration test for recovery after broker failure

Documentation

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

Matching PR in forked repository

PR in forked repository:

[codelipenghui]

/pulsarbot run-failure-checks

[codecov-commenter]

Codecov Report

Merging #20978 (2748b99) into master (9862884) will increase coverage by 39.60%.
Report is 7 commits behind head on master.
The diff coverage is 50.00%.

@@              Coverage Diff              @@
##             master   #20978       +/-   ##
=============================================
+ Coverage     33.53%   73.13%   +39.60%     
- Complexity    12174    32253    +20079     
=============================================
  Files          1621     1875      +254     
  Lines        126919   139407    +12488     
  Branches      13851    15329     +1478     
=============================================
+ Hits          42561   101955    +59394     
+ Misses        78745    29400    -49345     
- Partials       5613     8052     +2439     

Flag	Coverage Δ
inttests	24.09% <50.00%> (-0.19%)	⬇️
systests	25.10% <0.00%> (?)
unittests	72.42% <50.00%> (+40.37%)	⬆️

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

Files Changed	Coverage Δ
...g/apache/pulsar/compaction/CompactedTopicImpl.java	63.90% <0.00%> (+4.51%)	⬆️
...ulsar/compaction/PulsarTopicCompactionService.java	76.47% <100.00%> (ø)

... and 1520 files with indirect coverage changes