enhance: support null expr(#38772)

[smellthemoon]

pr: #38772
issue: #31728

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[codecov]

Codecov Report

Attention: Patch coverage is 89.62264% with 11 lines in your changes missing coverage. Please review.

Project coverage is 69.54%. Comparing base (4533fc8) to head (0ca36f5).
Report is 5 commits behind head on 2.5.

Files with missing lines	Patch %	Lines
internal/core/src/exec/expression/NullExpr.cpp	90.41%	7 Missing ⚠️
internal/core/src/expr/ITypeExpr.h	55.55%	4 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (4533fc8) and HEAD (0ca36f5). Click for more details.

HEAD has 2 uploads less than BASE

Flag	BASE (4533fc8)	HEAD (0ca36f5)
	3	1

Additional details and impacted files

@@             Coverage Diff             @@
##              2.5   #38931       +/-   ##
===========================================
- Coverage   81.12%   69.54%   -11.59%     
===========================================
  Files        1383      296     -1087     
  Lines      195517    26524   -168993     
===========================================
- Hits       158619    18446   -140173     
+ Misses      31355     8078    -23277     
+ Partials     5543        0     -5543     

Components	Coverage Δ
Client	∅ <ø> (∅)
Core	69.54% <89.62%> (+0.09%)	⬆️
Go	∅ <ø> (∅)

Files with missing lines	Coverage Δ
internal/core/src/common/Types.h	29.53% <ø> (ø)
...ernal/core/src/exec/expression/BinaryRangeExpr.cpp	93.01% <ø> (ø)
internal/core/src/exec/expression/Expr.cpp	94.40% <100.00%> (+0.24%)	⬆️
internal/core/src/exec/expression/NullExpr.h	100.00% <100.00%> (ø)
internal/core/src/exec/expression/UnaryExpr.cpp	84.58% <100.00%> (+0.06%)	⬆️
internal/core/src/query/PlanProto.cpp	88.79% <100.00%> (+0.34%)	⬆️
internal/core/src/query/PlanProto.h	18.51% <ø> (ø)
internal/core/src/expr/ITypeExpr.h	46.12% <55.55%> (+0.28%)	⬆️
internal/core/src/exec/expression/NullExpr.cpp	90.41% <90.41%> (ø)

... and 1090 files with indirect coverage changes

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