Fix missing tools in logs (#6532)

Fix for LLMCallEvent failing to log "tools" passed to
BaseOpenAIChatCompletionClient in
autogen_ext.models.openai._openai_client.BaseOpenAIChatCompletionClient

This bug creates problems inspecting why a certain tool was selected/not
selected by the LLM as the list of tools available to the LLM is not
present in the logs

## Why are these changes needed?

Added "tools" to the LLMCallEvent to log tools available to the LLM as
these were being missed causing difficulties during debugging LLM tool
calls.

## Related issue number

[<!-- For example: "Closes #1234"
-->](https://github.com/microsoft/autogen/issues/6531)

## Checks

- [x] I've included any doc changes needed for
<https://microsoft.github.io/autogen/>. See
<https://github.com/microsoft/autogen/blob/main/CONTRIBUTING.md> to
build and test documentation locally.
- [x] I've added tests (if relevant) corresponding to the changes
introduced in this PR.
- [x] I've made sure all auto checks have passed.

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Co-authored-by: Eric Zhu <ekzhu@users.noreply.github.com>