Fix PIT example in search.md

[mausch]

Description

Fix PIT example, it was using some old methods/APIs.

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.37%. Comparing base (ba715b9) to head (a8a43db).
Report is 78 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #869      +/-   ##
==========================================
- Coverage   71.95%   70.37%   -1.58%     
==========================================
  Files          91      125      +34     
  Lines        8001     9290    +1289     
==========================================
+ Hits         5757     6538     +781     
- Misses       2244     2752     +508     

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[dblock]

Thank you!

Want to add this as a working example to https://github.com/opensearch-project/opensearch-py/tree/main/samples? Let's make sure it runs?