docs: add YAML Toolset examples

[MukundaKatta]

Summary

• add a YAML example showing a serialized Toolset with multiple ComponentTools
• show how to pass the Toolset as the tools init parameter to OpenAIChatGenerator and ToolInvoker
• add a second YAML example showing the same Toolset inside an Agent definition

Closes #11163.

Testing

• not run (docs-only change)

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[sjrl]

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[sjrl]

Hey @MukundaKatta thanks for the contribution but after internal discussion we believe this case is already handled in our Agent docs and for now we don't think it's worth adding this into the toolset docs. So I'll be closing the PR.