fix: make stream_query_reasoning_engine async in AsyncClient

[olibook]

• Add async keyword to stream_query_reasoning_engine method
• Add await to rpc call in async client
• Use execution_async_client instead of execution_api_client
• Use async for loop to iterate over response stream

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Fixes #5773

This is a rebase of #5774

[olibook]

Hello @sararob ! do you mind having a look at action workflows ? requires an approval from a maintainer.

Cheers