.Net: Add float64 support for redis vector search.

[westey-m]

Motivation and Context

Redis supports float64 for vector storage, and the Redis connectors were supporting this as well, but not for search.

Description

• Adding float64 support for Redis vector search with tests.
• Changed from suing name to fullname for outputting the vector type name since name doesn't include the generic type.

#8846

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 😄