fix(rust): Implement is_nested_null for Null Array

[eitsupi]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.

Project coverage is 79.68%. Comparing base (ff10b38) to head (9d9fb5c).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/polars-core/src/datatypes/any_value.rs	0.00%	1 Missing ⚠️
crates/polars-core/src/datatypes/dtype.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #19219   +/-   ##
=======================================
  Coverage   79.67%   79.68%           
=======================================
  Files        1532     1532           
  Lines      209200   209202    +2     
  Branches     2417     2417           
=======================================
+ Hits       166687   166701   +14     
+ Misses      41965    41953   -12     
  Partials      548      548           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.