Add channel name paramter in FlushSegmentsRequest

[congqixia]

This PR add ChannelName parameter in FlushSegmentsRequest
Old datanode will ignore this parameter
New Datanodes with L0 delta may accelerate with this information and also be compatible with request without it
See also #27675

/kind improvement

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: congqixia

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• internal/datacoord/OWNERS [congqixia]
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[codecov]

Codecov Report

Merging #27725 (f22bf6e) into master (43f2452) will increase coverage by 0.10%.
Report is 4 commits behind head on master.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master   #27725      +/-   ##
==========================================
+ Coverage   81.52%   81.62%   +0.10%     
==========================================
  Files         806      807       +1     
  Lines      114267   114581     +314     
==========================================
+ Hits        93153    93525     +372     
+ Misses      17978    17909      -69     
- Partials     3136     3147      +11     

Files	Coverage Δ
internal/datacoord/cluster.go	92.00% <100.00%> (+0.10%)	⬆️

... and 30 files with indirect coverage changes

[yah01]

/lgtm