Fix: masked array dtype mismatch

[connortsui20]

Fixes: #5989

[codecov]

Codecov Report

❌ Patch coverage is 82.35294% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.93%. Comparing base (aa5d235) to head (875d367).
⚠️ Report is 1 commits behind head on develop.

Files with missing lines	Patch %	Lines
vortex-array/src/arrays/masked/vtable/mod.rs	82.35%	3 Missing ⚠️

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