fix(native): Handle null correctly as JsNull, not as JsString

[ovr]

No description provided.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.32%. Comparing base (40b3708) to head (3c049fa).
Report is 76 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9717      +/-   ##
==========================================
+ Coverage   84.20%   84.32%   +0.11%     
==========================================
  Files         230      234       +4     
  Lines       85315    86954    +1639     
==========================================
+ Hits        71842    73321    +1479     
- Misses      13473    13633     +160     

Flag	Coverage Δ
cubesql	84.32% <ø> (+0.11%)	⬆️

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[KSDaemon]

👍🏻 LGTM just fix cargo fmt...