fix(frontend): fix TopN in frontend to be compatible with current implementation

[fuyufjh]

What's changed and what's your intention?

The current implementation of TopN in Java frontend & compute node assumes its PK should be exactly the same with sort keys, so the PK of TopN = sort_key + input.pk. This PR changes Rust frontend's behavior to be compatible with that.

However, The PK of TopN should be the input's PK instead of sort_key + input.pk. To fix this, we need to change proto, compute nodes and rust & java frontend simultaneously. Let do this later.

I've also added some e2e tests for order-by queries.

Checklist

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

Refer to a related PR or issue link (optional)

[skyzh]

LGTM

[codecov]

Codecov Report

Merging #2129 (0e46b56) into main (564dd08) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #2129   +/-   ##
=======================================
  Coverage   70.83%   70.83%           
=======================================
  Files         640      640           
  Lines       81485    81501   +16     
=======================================
+ Hits        57717    57734   +17     
+ Misses      23768    23767    -1     

Flag	Coverage Δ
rust	70.83% <100.00%> (+<0.01%)	⬆️

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

Impacted Files	Coverage Δ
...c/frontend/src/optimizer/plan_node/logical_topn.rs	90.26% <100.00%> (ø)
...rc/frontend/src/optimizer/plan_node/stream_topn.rs	69.84% <100.00%> (+10.26%)	⬆️
src/common/src/types/ordered_float.rs	24.30% <0.00%> (+0.19%)	⬆️

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