Use Ukrainian VAT abbreviation for Ukraine tax name

[afurm]

What are you trying to accomplish?

Correct the Ukraine region tax name from the Latin transliteration PDV to the Ukrainian Cyrillic abbreviation ПДВ. The State Tax Service of Ukraine uses ПДВ for податок на додану вартість, including on its VAT registration guidance: https://tax.gov.ua/baneryi/onlayn-navchannya/reestratsiya-ta-oblik-yuridichnih-osib-ta-samozaynyatih-fizichnih-osib/reestratsiya-platnikiv-pdv/987813.html

What approach did you choose and why?

Updated data/regions/UA.yml to use the native Ukrainian abbreviation and added a focused regression assertion in RegionTest so the value stays covered.

What should reviewers focus on?

Whether ПДВ is the expected user-facing tax name for Ukraine in this data file.

The impact of these changes

Consumers reading Worldwide.region(code: "UA").tax_name now receive the Ukrainian abbreviation used in official tax materials instead of a Latin transliteration.

Testing

• RBENV_VERSION=3.4.7 bundle exec ruby -Itest test/worldwide/region_test.rb
• RBENV_VERSION=3.4.7 bundle exec ruby -Itest test/worldwide/region_yml_consistency_test.rb

Checklist

• I have added a CHANGELOG entry for this change (or determined that it is not needed)