Port dotnet feature: .Net: Refactor MEVD Vector Attribute and make Dimensions mandatory

[github-actions]

Original issue

#11490

Description

Motivation and Context

#11365
#11318

Description

• Make Dimensions property mandatory for both the Attribute and Definition Property
• Remove unnecessary constructor overloads for Vector attribute in favor of property setters.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the SK Contribution Guidelines and the pre-submission formatting script raises no violations
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄

\n Relates to #11490