docs(quickstart): clarify all-in-one includes model providers (#2425)

## Description

Fixes #840.

The V1 installation docs still told all-in-one users to manually add
OpenAI / Gemini / Anthropic SDKs, and used outdated `1.0.12` version
samples. The `agentscope` all-in-one artifact already shades the common
model extensions
(`agentscope-extensions-model-openai/gemini/anthropic/dashscope/ollama`)
and their required SDKs.