feat: [2.6] support use function scorer as ranker not one function

[aoiasd]

pr: #2992

[codecov]

Codecov Report

❌ Patch coverage is 58.62069% with 12 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (2.6@8b09a7c). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
pymilvus/client/prepare.py	57.14%	6 Missing ⚠️
pymilvus/orm/schema.py	50.00%	6 Missing ⚠️

Additional details and impacted files

@@          Coverage Diff           @@
##             2.6    #3010   +/-   ##
======================================
  Coverage       ?   46.23%           
======================================
  Files          ?       64           
  Lines          ?    12901           
  Branches       ?        0           
======================================
  Hits           ?     5965           
  Misses         ?     6936           
  Partials       ?        0           

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[czs007]

/lgtm

[sre-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aoiasd, czs007

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