API: Use FastAPI streaming instead of sse_starlette

sse_starlette kept firing a ping response if it was taking too long
to set an event. Rather than using a hacky workaround, switch to
FastAPI's inbuilt streaming response and construct SSE requests with
a utility function.

This helps the API become more robust and removes an extra requirement.

Signed-off-by: kingbri <bdashore3@proton.me>

utils.py

@@ -26,4 +26,7 @@ def get_generator_error(exception: Exception):
 
     # Log and send the exception
     print(f"\n{generator_error.error.trace}")
-    return generator_error.json()
+    return get_sse_packet(generator_error.json(ensure_ascii = False))
+
+def get_sse_packet(json_data: str):
+    return f"data: {json_data}\n\n"