feat: handle non-string returns from getmcptool

[tevanburen]

Description

We're updating RunMCPTool to return outputs of multiple types. This PR allows the SDK and Playground to handle these new returns
Goes with SEMOSS/Semoss#2030

Changes Made

Handle unknown return types

• In the default tool UI
• When auto-executing
• When using actions.runMCPTool in the SDK

How to Test

1. Have a tool that returns a non-string (for example, a map)
2. Set it up to not auto-execute, and not have a custom UI. Verify that it still works
3. Set it up to not auto-execute, and have a custom UI that calls actions.runMCPTool. Verify it still works
4. Set it up to auto-execute. Verify it still works

[github-actions]

@CodiumAI-Agent /update_changelog