refactor(stream): remove TopNStateError

[lmatz]

What's changed and what's your intention?

Similar to #3140.

Checklist

- [ ] I have written necessary docs and comments
- [ ] I have added necessary unit tests and integration tests

• All checks passed in ./risedev check (or alias, ./risedev c)

Refer to a related PR or issue link (optional)

closes #3134

[codecov]

Codecov Report

Merging #3142 (2bf1db1) into main (5922133) will increase coverage by 0.00%.
The diff coverage is 78.16%.

@@           Coverage Diff           @@
##             main    #3142   +/-   ##
=======================================
  Coverage   73.51%   73.52%           
=======================================
  Files         737      737           
  Lines      101650   101632   -18     
=======================================
- Hits        74725    74720    -5     
+ Misses      26925    26912   -13     

Flag	Coverage Δ
rust	73.52% <78.16%> (+<0.01%)	⬆️

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

Impacted Files	Coverage Δ
src/stream/src/executor/error.rs	5.63% <ø> (+0.22%)	⬆️
src/stream/src/executor/top_n.rs	91.58% <40.00%> (+0.54%)	⬆️
src/stream/src/executor/top_n_appendonly.rs	95.16% <50.00%> (+0.69%)	⬆️
...ecutor/managed_state/top_n/top_n_bottom_n_state.rs	77.63% <94.44%> (+0.66%)	⬆️
src/stream/src/executor/managed_state/top_n/mod.rs	100.00% <100.00%> (ø)
...am/src/executor/managed_state/top_n/top_n_state.rs	93.02% <100.00%> (+0.25%)	⬆️

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[BugenZhao]

LGTM!