HTTPPlugin : Add a builder option to provide custom server (enables providing options like ssl etc)

[MehakBindra]

Tested with code like (check running on and activities received on port 8000 )

def make_server(app: FastAPI) -> uvicorn.Server:
    config = uvicorn.Config(
        app=app,
        host="0.0.0.0",
        port=8000,
        log_level="debug",
    )
    return uvicorn.Server(config)


app = App(
    plugins=[
        DevToolsPlugin(),
        HttpPlugin(app_id=None, server_factory=make_server),
    ]
)

[Copilot]

Pull Request Overview

This PR adds support for custom server configuration in the HTTPPlugin by introducing a server_factory parameter. This enables users to provide their own pre-configured uvicorn server with custom options like SSL certificates, custom logging, or other server-level configurations.

Key Changes:

• Added optional server_factory parameter to HTTPPlugin constructor
• Modified startup logic to use custom server when provided, with port conflict detection
• Added documentation for the new parameter

[heyitsaamir]

Talked offline. This makes sense to me. Add the code comment and 🚢