Simplify the merge logic of searchTask

[czs007]

fix #17188
Signed-off-by: zhenshan.cao zhenshan.cao@zilliz.com

[codecov]

Codecov Report

Merging #17194 (907bda2) into master (2512e66) will increase coverage by 0.09%.
The diff coverage is 10.00%.

@@            Coverage Diff             @@
##           master   #17194      +/-   ##
==========================================
+ Coverage   80.46%   80.55%   +0.09%     
==========================================
  Files         460      460              
  Lines       72049    72044       -5     
==========================================
+ Hits        57975    58038      +63     
+ Misses      11452    11387      -65     
+ Partials     2622     2619       -3     

Impacted Files	Coverage Δ
internal/querynode/query_shard.go	79.03% <ø> (+12.78%)	⬆️
internal/querynode/task_search.go	0.00% <0.00%> (ø)
internal/proxy/task_search.go	61.62% <25.00%> (-0.28%)	⬇️
internal/proxy/util.go	85.71% <50.00%> (-0.52%)	⬇️
internal/distributed/querycoord/client/client.go	70.38% <0.00%> (-1.95%)	⬇️
internal/rootcoord/task.go	76.61% <0.00%> (-1.19%)	⬇️
internal/util/grpcclient/client.go	84.81% <0.00%> (-0.64%)	⬇️
internal/mq/msgstream/mq_msgstream.go	79.24% <0.00%> (-0.59%)	⬇️
internal/indexcoord/meta_table.go	83.29% <0.00%> (-0.52%)	⬇️
internal/rootcoord/meta_table.go	82.08% <0.00%> (-0.49%)	⬇️
... and 15 more

[xiaofan-luan]

/lgtm
/approve

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: czs007, xiaofan-luan

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• internal/proxy/OWNERS [czs007,xiaofan-luan]
• internal/querynode/OWNERS [czs007,xiaofan-luan]

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