Prompt version needs user information in Vertex AI Studio

For VertexAI prompts , the prompt version and history provides the timestamp of when the prompt was saved and the version id and prompt details. It does not provide the user who saved the prompt for both historical and current prompt version. This is critical requirement during team work.

Start with the Vertex AI Studio prompt version and history flow described in the issue, and determine where the current and historical version details are exposed. Done means both views identify the user who saved each prompt version, alongside the existing timestamp, version ID, and prompt details.

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