feat(frontend): support complex expr in group by

[Enter-tainer]

What's changed and what's your intention?

Previously, only InputRefs are allowed in the group by expression. This pr adds support for complex expressions in the group by.

Note that it seems that the current code already supports complex expressions in group by, so I only change the error code and the condition. Other chores like comment improvement and typo fix are also included in this pr.

Checklist

• I have written the necessary docs and comments
• I have added necessary unit tests and integration tests

Refer to a related PR or issue link (optional)

This pr resolves #1637.

[codecov]

Codecov Report

Merging #1899 (65cf3d1) into main (2880cef) will increase coverage by 0.00%.
The diff coverage is 90.90%.

@@           Coverage Diff           @@
##             main    #1899   +/-   ##
=======================================
  Coverage   70.60%   70.60%           
=======================================
  Files         611      611           
  Lines       79981    79995   +14     
=======================================
+ Hits        56467    56484   +17     
+ Misses      23514    23511    -3     

Flag	Coverage Δ
rust	70.60% <90.90%> (+<0.01%)	⬆️

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

Impacted Files	Coverage Δ
...rc/frontend/src/optimizer/plan_node/logical_agg.rs	97.56% <90.90%> (+0.20%)	⬆️
src/meta/src/manager/stream_clients.rs	96.29% <0.00%> (+7.40%)	⬆️

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[likg227]

LGTM