fix: [2.4] Decode unicode for json key in expression

[xiaocai2333]

issue: #38626

master pr: #38651

[czs007]

/approve
/lgtm

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.16%. Comparing base (e82af48) to head (f364ae8).
Report is 3 commits behind head on 2.4.

❗ There is a different number of reports uploaded between BASE (e82af48) and HEAD (f364ae8). Click for more details.

HEAD has 1 upload less than BASE

Flag	BASE (e82af48)	HEAD (f364ae8)
	2	1

Additional details and impacted files

@@            Coverage Diff             @@
##              2.4   #38652      +/-   ##
==========================================
- Coverage   80.44%   72.16%   -8.29%     
==========================================
  Files        1077     1077              
  Lines      169442   169450       +8     
==========================================
- Hits       136316   122278   -14038     
- Misses      28677    42701   +14024     
- Partials     4449     4471      +22     

Files with missing lines	Coverage Δ
internal/parser/planparserv2/parser_visitor.go	86.05% <100.00%> (+0.02%)	⬆️
internal/parser/planparserv2/plan_parser_v2.go	86.70% <ø> (-1.57%)	⬇️
internal/parser/planparserv2/utils.go	87.10% <100.00%> (+0.65%)	⬆️

... and 232 files with indirect coverage changes