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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