feat(expr): support array_to_string

[fuyufjh]

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What's changed and what's your intention?

Fixes #7764

Checklist

• I have written necessary rustdoc comments
• I have added necessary unit tests and integration tests
• I have added fuzzing tests or opened an issue to track them. (Optional, recommended for new SQL features).
• I have demonstrated that backward compatibility is not broken by breaking changes and created issues to track deprecated features to be removed in the future. (Please refer to the issue)
• All checks passed in ./risedev check (or alias, ./risedev c)

Documentation

My PR contains user-facing changes.

Types of user-facing changes

Please keep the types that apply to your changes, and remove the others.

• SQL commands, functions, and operators

Release note

See: https://www.postgresql.org/docs/current/functions-array.html#FUNCTION-ARRAY-TO-STRING

[github-actions]

license-eye has totally checked 2775 files.

Valid	Invalid	Ignored	Fixed
1317	1	1457	0

Click to see the invalid file list

• src/expr/src/expr/array.rs

[wangrunji0408]

Rest LGTM

[codecov]

Codecov Report

Merging #8027 (c84e4a8) into main (ae3b788) will decrease coverage by 0.05%.
The diff coverage is 7.93%.

@@            Coverage Diff             @@
##             main    #8027      +/-   ##
==========================================
- Coverage   71.36%   71.32%   -0.05%     
==========================================
  Files        1126     1127       +1     
  Lines      181255   181380     +125     
==========================================
+ Hits       129356   129367      +11     
- Misses      51899    52013     +114     

Flag	Coverage Δ
rust	71.32% <7.93%> (-0.05%)	⬇️

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

Impacted Files	Coverage Δ
src/common/src/types/to_text.rs	76.66% <ø> (ø)
src/expr/src/expr/build_expr_from_prost.rs	40.44% <0.00%> (-0.10%)	⬇️
src/expr/src/expr/expr_array_to_string.rs	0.00% <0.00%> (ø)
src/expr/src/expr/mod.rs	100.00% <ø> (ø)
src/frontend/src/expr/type_inference/func.rs	87.98% <28.57%> (-0.56%)	⬇️
src/expr/src/sig/func.rs	94.11% <100.00%> (+0.15%)	⬆️
src/frontend/src/binder/expr/function.rs	89.28% <100.00%> (+0.01%)	⬆️
src/common/src/types/ordered_float.rs	30.87% <0.00%> (-0.20%)	⬇️
src/storage/src/hummock/compactor/mod.rs	80.69% <0.00%> (-0.20%)	⬇️
src/common/src/types/mod.rs	73.47% <0.00%> (+0.42%)	⬆️

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[wangrunji0408]

I just realized that the evaluate functions can be further optimized to the writer style. Pushed a commit b8e568f. PTAL