[DO NOT MERGE - triggering tests] Egalpin/refactor broker request handle request

[egalpin]

Instructions:

1. The PR has to be tagged with at least one of the following labels (*):
   1. feature
   2. bugfix
   3. performance
   4. ui
   5. backward-incompat
   6. release-notes (**)
2. Remove these instructions before publishing the PR.

(*) Other labels to consider:

• testing
• dependencies
• docker
• kubernetes
• observability
• security
• code-style
• extension-point
• refactor
• cleanup

(**) Use release-notes label for scenarios like:

• New configuration options
• Deprecation of configurations
• Signature changes to public methods/interfaces
• New plugins added or old plugins removed

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 52.31317% with 268 lines in your changes missing coverage. Please review.

Project coverage is 63.81%. Comparing base (59551e4) to head (e26bc9d). Report is 2306 commits behind head on master.

Files with missing lines	Patch %	Lines
...sthandler/BaseSingleStageBrokerRequestHandler.java	43.55%	118 Missing and 44 partials :warning:
...r/spark/common/reader/PinotServerDataFetcher.scala	0.00%	21 Missing :warning:
...pache/pinot/core/transport/AsyncQueryResponse.java	69.56%	17 Missing and 4 partials :warning:
...roker/requesthandler/GrpcBrokerRequestHandler.java	0.00%	12 Missing :warning:
...thandler/SingleConnectionBrokerRequestHandler.java	0.00%	11 Missing :warning:
...rg/apache/pinot/core/transport/ServerChannels.java	47.05%	5 Missing and 4 partials :warning:
...a/org/apache/pinot/core/transport/QueryRouter.java	80.55%	5 Missing and 2 partials :warning:
...rg/apache/pinot/core/transport/ServerInstance.java	33.33%	3 Missing and 1 partial :warning:
...e/pinot/core/query/reduce/BrokerReduceService.java	86.95%	2 Missing and 1 partial :warning:
...e/pinot/core/query/request/ServerQueryRequest.java	66.66%	3 Missing :warning:
... and 9 more

Additional details and impacted files

@@             Coverage Diff              @@
##             master   #14213      +/-   ##
============================================
+ Coverage     61.75%   63.81%   +2.06%     
- Complexity      207     1550    +1343     
============================================
  Files          2436     2663     +227     
  Lines        133233   145997   +12764     
  Branches      20636    22350    +1714     
============================================
+ Hits          82274    93171   +10897     
- Misses        44911    45942    +1031     
- Partials       6048     6884     +836     

Flag	Coverage Δ
custom-integration1	?
integration	?
integration1	?
integration2	?
java-11	55.47% <73.45%> (-6.23%)	:arrow_down:
java-21	63.70% <52.31%> (+2.08%)	:arrow_up:
skip-bytebuffers-false	63.80% <52.31%> (+2.05%)	:arrow_up:
skip-bytebuffers-true	63.68% <52.31%> (+35.95%)	:arrow_up:
temurin	63.81% <52.31%> (+2.06%)	:arrow_up:
unittests	63.81% <52.31%> (+2.06%)	:arrow_up:
unittests1	55.50% <73.45%> (+8.61%)	:arrow_up:
unittests2	34.17% <24.91%> (+6.44%)	:arrow_up:

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