.Net: Expose GeminiKernelFunctionMetadataExtensions

[JanainaLudwig]

Motivation and Context

GeminiToolCallBehavior exposes the method EnableFunctions to enable filtering which Kernel Functions are available for auto invoke. However, there's no way to construct a GeminiFunction instance since the constructor is internal.

I saw there's an extension to build a GeminiFunction from a KernelFunctionMetadata, but it's under the test project. It seems that it was supposed to be exposed from the library, since there's also a test file for KernelFunctionMetadata.

This way, it will be possible to use GeminiToolCallBehavior.EnableFunctions to explicitly specify which tools can be auto-called by the Google connector.

Description

• Move GeminiKernelFunctionMetadataExtensions from SemanticKernel.Connectors.Google.UnitTests to Microsoft.SemanticKernel.Connectors.Google.Extensions namespace.
• Remove FunctionMetadataAsGeminiFunction and start using GeminiKernelFunctionMetadataExtensions instead.

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 😄

[JanainaLudwig]

@microsoft-github-policy-service agree