…1790)

### Motivation and Context
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Method `SaveInformationAsync` of kernel memory type should be idempotent
to update memory record with same key multiple times. This PR contains
changes to allow that behavior in Chroma connector and tests to verify
it.

### Description
<!-- Describe your changes, the overall approach, the underlying design.
These notes will help understanding how your code works. Thanks! -->
1. Replaced Chroma `POST /collections/{collection_id}/add` with `POST
collections/{collection_id}/upsert` to allow idempotent behavior.
2. Added integration tests to verify scenario with adding/updating
memory record with same key multiple times.

### Contribution Checklist
<!-- Before submitting this PR, please make sure: -->
- [x] The code builds clean without any errors or warnings
- [x] The PR follows SK Contribution Guidelines
(https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
- [x] The code follows the .NET coding conventions
(https://learn.microsoft.com/dotnet/csharp/fundamentals/coding-style/coding-conventions)
verified with `dotnet format`
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄