Rust value tests

[benjaminwinger]

I've re-enabled some rust tests which had been disabled due to them not being fully supported as they now appear to be working.
Passing unions as parameters still doesn't seem to be supported, however I noticed a change to how union tags are handled which hadn't been propagated to the rust API, so I moved the tag type details into the LogicalType::UNION function to handle them all in one place.

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 lines in your changes are missing coverage. Please review.

Project coverage is 93.37%. Comparing base (b491af2) to head (6f52967).
Report is 81 commits behind head on master.

❗ Current head 6f52967 differs from pull request most recent head 5f9f4e7

Please upload reports for the commit 5f9f4e7 to get more accurate results.

Files	Patch %	Lines
src/common/types/value/nested.cpp	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2708      +/-   ##
==========================================
+ Coverage   92.59%   93.37%   +0.78%     
==========================================
  Files        1205     1073     -132     
  Lines       44825    40432    -4393     
==========================================
- Hits        41504    37754    -3750     
+ Misses       3321     2678     -643     

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