[Backport 2.17] [Backport 2.x] IF function should support complex predicates in PPL

[opensearch-trigger-bot]

Backport 1e95b68 from #2969.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.51%. Comparing base (f51bf56) to head (9953794).
Report is 2 commits behind head on 2.17.

Additional details and impacted files

@@            Coverage Diff            @@
##               2.17    #2970   +/-   ##
=========================================
  Coverage     94.51%   94.51%           
  Complexity     5265     5265           
=========================================
  Files           518      518           
  Lines         14952    14952           
  Branches        978      978           
=========================================
  Hits          14132    14132           
  Misses          773      773           
  Partials         47       47           

Flag	Coverage Δ
sql-engine	94.51% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.