Motivation and Context

Complete the implementation of VolatileMemoryStoreTests

Description

Complete the implementation of VolatileMemoryStoreTests. Make implementation consistent with tests.

Please note that I added equals and hashCode methods to Embedding, MemoryRecord, and MemoryRecordMetadata because these unit tests use assertEquals. Alternatively, I could have created methods in VolatileMemoryStoreTests to check equality. I'm good with either way.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows SK Contribution Guidelines (https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
• The code follows the .NET coding conventions (https://learn.microsoft.com/dotnet/csharp/fundamentals/coding-style/coding-conventions) verified with dotnet format Java code follows AOSP style
• All unit tests pass, and I have added new tests where possible
• I didn't break anyone 😄