fix: Address exception send_message_to_agent() missing 1 required positional argument: 'stream_legacy' on 'v1/chat/completions'

[vysona-scott]

Please describe the purpose of this pull request.
Bug fix
I am not sure that hard coding the stream_legacy to False is appropriate, open to feedback.

How to test
How can we test your PR during review? What commands should we run? What outcomes should we expect?

curl --location 'http://localhost:8083/v1/chat/completions' \
--header 'Authorization: Bearer <TOKEN>' \
--header 'Content-Type: application/json' \
--data '{
    "messages": [
        {
            "id": "UnzuNq8",
            "createdAt": "2024-07-29T14:14:10.412Z",
            "role": "user",
            "content": "ssssss"
        }
    ],
    "user": "355e3a6a-7176-42d6-a4b0-09db2d202a0f",
    "model":"gpt-4o",
    "requestData": {}
}'

Have you tested this PR?
Have you tested the latest commit on the PR? If so please provide outputs from your tests.
Yes

dotenv run -- memgpt server
Using existing admin server password from environment.
User ID: 00000000-0000-0000-0000-000000000000
DEBUG False
Running: uvicorn server:app --host localhost --port 8283
INFO:     Started server process [1537306]
INFO:     Waiting for application startup.
Writing out openapi_memgpt.json file
Writing out openapi_assistants.json file
INFO:     Application startup complete.
INFO:     Uvicorn running on http://localhost:8283 (Press CTRL+C to quit)
Starting non-streaming OpenAI proxy response
MemGPT.memgpt.server.server - INFO - Grabbing agent user_id=8bae8a8c-47f5-4a36-9553-0c988464f417 agent_id=355e3a6a-7176-42d6-a4b0-09db2d202a0f from database
MemGPT.memgpt.server.server - INFO - Creating an agent object
MemGPT.memgpt.server.server - INFO - Adding agent to the agent cache: user_id=8bae8a8c-47f5-4a36-9553-0c988464f417, agent_id=355e3a6a-7176-42d6-a4b0-09db2d202a0f
Skipping message: {'internal_monologue': 'The user repeated the same question. Should check for deeper engagement or issues.', 'date': '2024-07-29T19:13:09.496714+00:00', 'id': '8059ef6d-c3ba-41f0-91c4-531c9d7cf2a4'}
Failed to parse MemGPT message: {'name': 'send_message', 'arguments': '{"message": "Hey again! I\'m still doing well. How about you? What\'s been on your mind lately?"}'}
Skipping message: {'function_return': 'None', 'status': 'success', 'id': 'ab2be711-bd76-45e3-9703-088abc3238ed', 'date': '2024-07-29T19:13:09.496934+00:00'}
INFO:     127.0.0.1:56448 - "POST /v1/chat/completions HTTP/1.1" 200 OK

Related issues or PRs
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#1591

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[cpacker]

LGTM, thank you!